Measurements

Area - Surface area of cones
Area - Surface area of spheres and hemispheres

By the end of the lesson, the learner should be able to:
- Define a cone and identify its parts
- Derive the formula for curved surface area
- Calculate surface area of solid cones

In groups, learners are guided to:
- Draw and cut a circle from manila paper
- Divide into two parts and fold to make a cone
- Identify slant height and radius
- Derive formula: πrl for curved surface
- Calculate total surface area: πrl + πr²
- Solve practical problems

How do we find the surface area of a cone?

- Master Mathematics Grade 9 pg. 85
- Manila paper
- Scissors
- Compasses and rulers
- Reference materials
- Spherical balls
- Rectangular paper
- Rulers
- Calculators

- Observation - Oral questions - Written assignments

Measurements

Volume - Volume of triangular prisms
Volume - Volume of rectangular prisms

By the end of the lesson, the learner should be able to:
- Define a prism
- Identify uniform cross-sections
- Calculate volume of triangular prisms

In groups, learners are guided to:
- Make a triangular prism using locally available materials
- Place prism vertically and fill with sand
- Identify the cross-section
- Apply formula: V = Area of cross-section × length
- Calculate area of triangular cross-section
- Multiply by length to get volume

How do we find the volume of a prism?

- Master Mathematics Grade 9 pg. 102
- Straws and paper
- Sand or soil
- Measuring tools
- Reference books
- Cuboid models
- Calculators
- Charts
- Reference materials

- Observation - Oral questions - Written assignments

Measurements

Volume - Volume of square-based pyramids
Volume - Volume of rectangular-based pyramids

By the end of the lesson, the learner should be able to:
- Define a right pyramid
- Relate pyramid volume to cube volume
- Calculate volume of square-based pyramids

In groups, learners are guided to:
- Model a cube and pyramid with same base and height
- Fill pyramid with soil and transfer to cube
- Observe that pyramid is ⅓ of cube
- Apply formula: V = ⅓ × base area × height
- Calculate volumes of square-based pyramids

How do we find the volume of a pyramid?

- Master Mathematics Grade 9 pg. 102
- Modeling materials
- Soil or sand
- Rulers
- Calculators
- Pyramid models
- Graph paper
- Reference books

- Observation - Oral questions - Written assignments

Measurements

Volume - Volume of triangular-based pyramids

By the end of the lesson, the learner should be able to:
- Calculate area of triangular bases
- Apply Pythagoras theorem where necessary
- Calculate volume of triangular-based pyramids

In groups, learners are guided to:
- Calculate area of triangular base (using ½bh)
- For equilateral triangles, use Pythagoras to find height
- Apply formula: V = ⅓ × (½bh) × H
- Solve problems with different triangular bases

How do we find volume of triangular pyramids?

- Master Mathematics Grade 9 pg. 102
- Triangular pyramid models
- Rulers
- Calculators
- Charts

- Observation - Oral questions - Written assignments

Measurements

Volume - Introduction to volume of cones
Volume - Calculating volume of cones

By the end of the lesson, the learner should be able to:
- Define a cone as a circular-based pyramid
- Relate cone volume to cylinder volume
- Derive the volume formula for cones

In groups, learners are guided to:
- Model a cylinder and cone with same radius and height
- Fill cone with water and transfer to cylinder
- Observe that cone is ⅓ of cylinder
- Derive formula: V = ⅓πr²h
- Use digital devices to watch videos

How is a cone related to a cylinder?

- Master Mathematics Grade 9 pg. 102
- Cone and cylinder models
- Water
- Digital devices
- Internet access
- Cone models
- Calculators
- Graph paper
- Reference materials

- Observation - Oral questions - Written tests

Measurements

Volume - Volume of frustums of pyramids
Volume - Volume of frustums of cones

By the end of the lesson, the learner should be able to:
- Define a frustum
- Explain how to obtain a frustum
- Calculate volume of frustums of pyramids

In groups, learners are guided to:
- Model a pyramid and cut it parallel to base
- Identify the frustum formed
- Calculate volume of original pyramid
- Calculate volume of small pyramid cut off
- Apply formula: Volume of frustum = V(large) - V(small)

What is a frustum and how do we find its volume?

- Master Mathematics Grade 9 pg. 102
- Pyramid models
- Cutting tools
- Rulers
- Calculators
- Cone models
- Frustum examples
- Reference books

- Observation - Oral questions - Written tests

Measurements

Volume - Volume of spheres
Volume - Volume of hemispheres and applications

By the end of the lesson, the learner should be able to:
- Relate sphere volume to cone volume
- Derive the formula for volume of a sphere
- Calculate volumes of spheres

In groups, learners are guided to:
- Select hollow spherical object
- Model cone with same radius and height 2r
- Fill cone and transfer to sphere
- Observe that 2 cones fill the sphere
- Derive formula: V = 4/3πr³
- Calculate volumes with different radii

How do we find the volume of a sphere?

- Master Mathematics Grade 9 pg. 102
- Hollow spheres
- Cone models
- Water or soil
- Calculators
- Hemisphere models
- Real objects
- Reference materials

- Observation - Oral questions - Written tests

Measurements

Mass, Volume, Weight and Density - Conversion of units of mass

By the end of the lesson, the learner should be able to:
- Define mass and state its SI unit
- Identify different units of mass
- Convert between different units of mass

In groups, learners are guided to:
- Use balance to measure mass of objects
- Record masses in grams
- Study conversion table for mass units
- Convert between kg, g, mg, tonnes, etc.
- Apply conversions to real situations

How do we convert between different units of mass?

- Master Mathematics Grade 9 pg. 111
- Weighing balances
- Various objects
- Conversion charts
- Calculators

- Observation - Oral questions - Written tests

Measurements

Mass, Volume, Weight and Density - More practice on mass conversions
Mass, Volume, Weight and Density - Relationship between mass and weight

By the end of the lesson, the learner should be able to:
- Convert masses to kilograms
- Apply conversions in real-life contexts
- Appreciate the importance of mass measurements

In groups, learners are guided to:
- Convert various masses to kilograms
- Work with large masses (tonnes)
- Work with small masses (milligrams, micrograms)
- Solve practical problems (construction, medicine, shopping)

Why is it important to convert units of mass?

- Master Mathematics Grade 9 pg. 111
- Conversion tables
- Calculators
- Real-world examples
- Reference books
- Spring balances
- Various objects
- Charts

- Observation - Oral questions - Written assignments

Measurements

Mass, Volume, Weight and Density - Calculating mass and gravity
Mass, Volume, Weight and Density - Introduction to density

By the end of the lesson, the learner should be able to:
- Calculate mass when given weight
- Calculate gravity of different planets
- Apply weight formula in different contexts

In groups, learners are guided to:
- Rearrange formula to find mass: m = W/g
- Rearrange formula to find gravity: g = W/m
- Compare gravity on Earth, Moon, and other planets
- Solve problems involving astronauts on different planets

How do we calculate mass and gravity from weight?

- Master Mathematics Grade 9 pg. 111
- Calculators
- Charts showing planetary data
- Reference materials
- Digital devices
- Weighing balances
- Measuring cylinders
- Water
- Containers

- Observation - Oral questions - Written assignments

Measurements

Mass, Volume, Weight and Density - Calculating density, mass and volume
Mass, Volume, Weight and Density - Applications of density

By the end of the lesson, the learner should be able to:
- Apply density formula to find density
- Calculate mass using density formula
- Calculate volume using density formula

In groups, learners are guided to:
- Apply formula: D = M/V to find density
- Rearrange to find mass: M = D × V
- Rearrange to find volume: V = M/D
- Convert between g/cm³ and kg/m³
- Solve various problems

How do we use the density formula?

- Master Mathematics Grade 9 pg. 111
- Calculators
- Charts with formulas
- Various solid objects
- Reference books
- Density tables
- Real-world scenarios
- Reference materials

- Observation - Oral questions - Written assignments

Measurements

Time, Distance and Speed - Working out speed in km/h and m/s

By the end of the lesson, the learner should be able to:
- Define speed
- Calculate speed in km/h
- Calculate speed in m/s
- Convert between km/h and m/s

In groups, learners are guided to:
- Go to field and mark two points 100 m apart
- Measure distance between points
- Time a person running between points
- Calculate speed: Speed = Distance/Time
- Calculate speed in m/s using metres and seconds
- Convert distance to kilometers and time to hours
- Calculate speed in km/h
- Convert km/h to m/s (divide by 3.6)
- Convert m/s to km/h (multiply by 3.6)

How do we calculate speed in different units?

- Master Mathematics Grade 9 pg. 117
- Stopwatches
- Tape measures
- Open field
- Calculators
- Conversion charts

- Observation - Oral questions - Written assignments

Measurements

Time, Distance and Speed - Calculating distance and time from speed
Time, Distance and Speed - Working out average speed

By the end of the lesson, the learner should be able to:
- Rearrange speed formula to find distance
- Rearrange speed formula to find time
- Solve problems involving speed, distance and time
- Apply to real-life situations

In groups, learners are guided to:
- Apply formula: Distance = Speed × Time
- Apply formula: Time = Distance/Speed
- Solve problems with different units
- Apply to journeys, races, train travel
- Work with Madaraka Express train problems
- Calculate distances covered at given speeds
- Calculate time taken for journeys

How do we calculate distance and time from speed?

- Master Mathematics Grade 9 pg. 117
- Calculators
- Formula charts
- Real-world examples
- Reference materials
- Field with marked points
- Stopwatches
- Reference books

- Observation - Oral questions - Written tests

Measurements

Time, Distance and Speed - Determining velocity
Time, Distance and Speed - Working out acceleration

By the end of the lesson, the learner should be able to:
- Define velocity
- Distinguish between speed and velocity
- Calculate velocity with direction
- Appreciate the importance of direction in velocity

In groups, learners are guided to:
- Define velocity as speed in a given direction
- Identify that velocity includes direction
- Calculate velocity for objects moving in straight lines
- Understand that velocity can be positive or negative
- Understand that same speed in opposite directions means different velocities
- Apply to real situations involving directional movement

What is the difference between speed and velocity?

- Master Mathematics Grade 9 pg. 117
- Diagrams showing direction
- Calculators
- Charts
- Reference materials
- Field for activity
- Stopwatches
- Measuring tools
- Formula charts

- Observation - Oral questions - Written tests

Measurements

Time, Distance and Speed - Deceleration and applications
Time, Distance and Speed - Identifying longitudes on the globe

By the end of the lesson, the learner should be able to:
- Define deceleration (retardation)
- Calculate deceleration
- Distinguish between acceleration and deceleration
- Solve problems involving both acceleration and deceleration
- Appreciate safety implications

In groups, learners are guided to:
- Define deceleration as negative acceleration
- Calculate when final velocity is less than initial velocity
- Apply to vehicles slowing down, braking
- Apply to matatus crossing speed bumps
- Understand safety implications of deceleration
- Calculate final velocity given acceleration and time
- Solve problems on cars, buses, gazelles
- Discuss importance of controlled deceleration for safety

What is deceleration and why is it important for safety?

- Master Mathematics Grade 9 pg. 117
- Calculators
- Road safety materials
- Charts
- Reference materials
- Globes
- Atlases
- World maps

- Observation - Oral questions - Written tests

Measurements

Time, Distance and Speed - Relating longitudes to time

By the end of the lesson, the learner should be able to:
- Explain relationship between longitudes and time
- State that Earth rotates 360° in 24 hours
- Calculate that 1° = 4 minutes
- Understand time zones and GMT

In groups, learners are guided to:
- Understand Earth rotates 360° in 24 hours
- Calculate: 360° = 24 hours = 1440 minutes
- Therefore: 1° = 4 minutes
- Identify time zones on world map
- Understand GMT (Greenwich Mean Time)
- Learn that places East of Greenwich are ahead in time
- Learn that places West of Greenwich are behind in time
- Use digital devices to check time zones

How are longitudes related to time?

- Master Mathematics Grade 9 pg. 117
- Globes
- Time zone maps
- Calculators
- Digital devices

- Observation - Oral questions - Written tests

Measurements

Time, Distance and Speed - Calculating time differences between places
Time, Distance and Speed - Determining local time of places along different longitudes

By the end of the lesson, the learner should be able to:
- Calculate longitude differences
- Calculate time differences between places
- Apply rules for same side and opposite sides of Greenwich
- Convert time differences to hours and minutes

In groups, learners are guided to:
- Find longitude difference:
• Subtract longitudes if on same side of Greenwich
• Add longitudes if on opposite sides of Greenwich
- Multiply longitude difference by 4 minutes
- Convert minutes to hours and minutes
- Determine if place is ahead or behind GMT
- Solve problems on towns X and Z, Memphis and Kigali
- Complete tables with longitude and time differences

How do we calculate time difference from longitudes?

- Master Mathematics Grade 9 pg. 117
- Atlases
- Calculators
- Time zone charts
- Reference books
- World maps
- Time zone references
- Real-world scenarios

- Observation - Oral questions - Written assignments

Measurements

Money - Identifying currencies of different countries
Money - Converting foreign currency to Kenyan shillings

By the end of the lesson, the learner should be able to:
- Identify currencies used in different countries
- State the Kenyan currency and its abbreviation
- Match countries with their currencies
- Appreciate diversity in world currencies

In groups, learners are guided to:
- Use digital devices to search for pictures of currencies
- Identify currencies of Britain, Uganda, Tanzania, USA, Rwanda, South Africa
- Make a collage of currencies from African countries
- Complete tables matching countries with their currencies
- Study Kenya shilling and its subdivision into cents
- Discuss the importance of different currencies

What currencies are used in different countries?

- Master Mathematics Grade 9 pg. 131
- Digital devices
- Internet access
- Pictures of currencies
- Atlases
- Reference materials
- Currency conversion tables
- Calculators
- Charts

- Observation - Oral questions - Written assignments - Project work

Measurements

Money - Converting Kenyan shillings to foreign currency and buying/selling rates
Money - Export duty on goods

By the end of the lesson, the learner should be able to:
- Convert Kenyan shillings to foreign currencies
- Distinguish between buying and selling rates
- Apply correct rates when converting currency
- Solve multi-step currency problems

In groups, learners are guided to:
- Convert Ksh to Ugandan shillings, Sterling pounds, Japanese Yen
- Study Table 3.5.2 showing buying and selling rates
- Understand that banks buy at lower rate, sell at higher rate
- Learn when to use buying rate (foreign to Ksh)
- Learn when to use selling rate (Ksh to foreign)
- Solve tourist problems with multiple conversions
- Visit commercial banks or Forex Bureaus

Why do buying and selling rates differ?

- Master Mathematics Grade 9 pg. 131
- Exchange rate tables
- Calculators
- Real-world scenarios
- Reference books
- Examples of export goods
- Charts
- Reference materials

- Observation - Oral questions - Written assignments

Measurements

Money - Import duty on goods
Money - Excise duty and Value Added Tax (VAT)

By the end of the lesson, the learner should be able to:
- Define import and import duty
- Calculate customs value of imported goods
- Calculate import duty on goods
- Apply knowledge to real-life situations

In groups, learners are guided to:
- Discuss goods imported into Kenya
- Learn about Kenya Revenue Authority (KRA)
- Calculate customs value: Cost + Insurance + Freight
- Apply formula: Import duty = Tax rate × Customs value
- Solve problems on vehicles, electronics, tractors, phones
- Discuss ways to reduce imports
- Understand importance of local production

What is import duty and how is it calculated?

- Master Mathematics Grade 9 pg. 131
- Calculators
- Import duty examples
- Charts
- Reference books
- Digital devices
- ETR receipts
- Tax rate tables
- Reference materials

- Observation - Oral questions - Written assignments

Measurements

Money - Combined duties and taxes on imported goods

By the end of the lesson, the learner should be able to:
- Calculate multiple taxes on imported goods
- Apply import duty, excise duty, and VAT sequentially
- Solve complex problems involving all taxes
- Appreciate the cumulative effect of taxes

In groups, learners are guided to:
- Calculate import duty first
- Calculate excise value: Customs value + Import duty
- Calculate excise duty on excise value
- Calculate VAT value: Customs value + Import duty + Excise duty
- Calculate VAT on VAT value
- Apply to vehicles, electronics, cement, phones
- Solve comprehensive taxation problems
- Work backwards to find customs value

How do we calculate total taxes on imported goods?

- Master Mathematics Grade 9 pg. 131
- Calculators
- Comprehensive examples
- Charts showing tax flow
- Reference materials

- Observation - Oral questions - Written assignments

Measurements

Approximations and Errors - Approximating quantities in measurements
Approximations and Errors - Determining errors using estimations and actual measurements

By the end of the lesson, the learner should be able to:
- Define approximation
- Approximate quantities using arbitrary units
- Use estimation in various contexts
- Appreciate the use of approximations in daily life

In groups, learners are guided to:
- Estimate length of teacher's table using palm length
- Estimate height of classroom door in metres
- Estimate width of textbook using palm
- Approximate distance using strides
- Approximate weight, capacity, temperature, time
- Use arbitrary units like strides and palm lengths
- Understand that approximations are not accurate
- Apply approximations in budgeting and planning

What is approximation and when do we use it?

- Master Mathematics Grade 9 pg. 146
- Tape measures
- Various objects to measure
- Containers for capacity
- Reference materials
- Measuring cylinders
- Water bottles
- Weighing scales
- Calculators

- Observation - Oral questions - Practical activities

Measurements

Approximations and Errors - Calculating percentage error
Approximations and Errors - Percentage error in real-life situations

By the end of the lesson, the learner should be able to:
- Define percentage error
- Calculate percentage error from approximations
- Express error as a percentage of actual value
- Compare errors using percentages

In groups, learners are guided to:
- Make strides and estimate total distance
- Measure actual distance covered
- Calculate error: Estimated value - Actual value
- Apply formula: Percentage error = (Error/Actual value) × 100%
- Solve problems on pavement width
- Calculate percentage errors in various measurements
- Round answers appropriately

How do we calculate percentage error?

- Master Mathematics Grade 9 pg. 146
- Tape measures
- Calculators
- Open ground for activities
- Reference books
- Real-world scenarios
- Case studies
- Reference materials

- Observation - Oral questions - Written tests

Measurements
4.0 Geometry

Approximations and Errors - Complex applications and problem-solving
4.3 Similarity and Enlargement - Similar figures

By the end of the lesson, the learner should be able to:
- Solve complex problems involving percentage errors
- Apply error calculations to budgeting and planning
- Evaluate the impact of errors
- Emphasize honesty and integrity in approximations

In groups, learners are guided to:
- Calculate percentage errors in fuel consumption estimates
- Work on budget estimation errors (school fuel budgets)
- Solve problems on athlete timing and weight
- Apply to construction cost estimates
- Analyze large errors and their consequences
- Discuss ways to minimize errors
- Emphasize ethical considerations in approximations
- Solve comprehensive review problems

How can we minimize errors and ensure accuracy?

- Master Mathematics Grade 9 pg. 146
- Calculators
- Complex scenarios
- Charts
- Reference books
- Real-world case studies
- Master Mathematics Grade 9 pg. 185
- Various objects
- Cut-outs of shapes
- Models

- Observation - Oral questions - Written tests - Project work

4.0 Geometry

4.3 Similarity and Enlargement - Properties of similar figures (1)

By the end of the lesson, the learner should be able to:
- State the properties of similar figures
- Measure corresponding sides and determine ratios accurately
- Appreciate that ratios of corresponding sides are constant

The learner is guided to:
- Trace similar triangles
- Measure lengths of corresponding sides
- Determine ratios of corresponding sides
- Observe that the ratios are equal

What is the relationship between sides of similar figures?

- Master Mathematics Grade 9 pg. 186
- Rulers
- Tracing papers
- Calculators
- Pencils

- Class activities - Written assignments

4.0 Geometry

4.3 Similarity and Enlargement - Properties of similar figures (2)
4.3 Similarity and Enlargement - Drawing similar figures

By the end of the lesson, the learner should be able to:
- Identify that corresponding angles of similar figures are equal
- Use properties to determine unknown sides and angles
- Develop interest in applying properties of similar figures

The learner is guided to:
- Measure corresponding angles of similar figures
- Observe that corresponding angles are equal
- Use ratio of sides to find unknown lengths
- Solve problems involving similar figures

How do we use properties of similar figures?

- Master Mathematics Grade 9 pg. 186
- Protractors
- Rulers
- Calculators
- Practice worksheets
- Master Mathematics Grade 9 pg. 189
- Compasses
- Plain papers

- Written tests - Oral questions

4.0 Geometry

4.3 Similarity and Enlargement - Determining properties of enlargement
4.3 Similarity and Enlargement - Positive scale factor (1)

By the end of the lesson, the learner should be able to:
- Define centre of enlargement and scale factor
- Locate the centre of enlargement and determine scale factor
- Appreciate that enlargements produce similar figures

The learner is guided to:
- Join corresponding points of objects and images
- Locate the centre where lines meet
- Measure distances from centre to object and image
- Calculate the scale factor

What is the relationship between object and image in enlargement?

- Master Mathematics Grade 9 pg. 190
- Rulers
- Compasses
- Tracing papers
- Models
- Master Mathematics Grade 9 pg. 192
- Graph papers
- Pencils

- Class activities - Written assignments

4.0 Geometry

4.3 Similarity and Enlargement - Positive scale factor (2)
4.3 Similarity and Enlargement - Negative scale factor (1)

By the end of the lesson, the learner should be able to:
- Describe what happens when scale factor is between 0 and 1
- Draw enlargements with fractional scale factors accurately
- Appreciate comparing enlargements with different positive scale factors

The learner is guided to:
- Draw enlargements with fractional scale factors
- Observe that images are smaller than objects
- Note that object and image remain upright
- Practice with various positive scale factors

What happens when the scale factor is between 0 and 1?

- Master Mathematics Grade 9 pg. 192
- Rulers
- Compasses
- Plain papers
- Models
- Master Mathematics Grade 9 pg. 196
- Graph papers
- Tracing papers

- Class activities - Written assignments

4.0 Geometry

4.3 Similarity and Enlargement - Negative scale factor (2)

By the end of the lesson, the learner should be able to:
- Explain the process of determining negative scale factors
- Locate centres of enlargement and apply negative scale factors to various figures
- Appreciate solving problems involving negative enlargements

The learner is guided to:
- Join corresponding vertices to locate centres
- Calculate scale factors from measurements
- Draw enlargements of different shapes with negative scale factors
- Solve problems involving negative enlargements

How do we work with negative scale factors?

- Master Mathematics Grade 9 pg. 196
- Rulers
- Compasses
- Plain papers
- Calculators

- Written tests - Class activities

4.0 Geometry

4.3 Similarity and Enlargement - Enlargement on the Cartesian plane (1)
4.3 Similarity and Enlargement - Enlargement on the Cartesian plane (2)

By the end of the lesson, the learner should be able to:
- State the rule (x,y) → (kx, ky) for enlargement with centre at origin
- Plot and enlarge figures accurately with centre at origin
- Develop interest in applying enlargement rules on coordinate axes

The learner is guided to:
- Plot given points on Cartesian plane
- Apply scale factor to coordinates
- Plot image points and join them
- Verify using measurement from origin

How do we enlarge figures on coordinate axes?

- Master Mathematics Grade 9 pg. 198
- Graph papers
- Rulers
- Calculators
- Pencils
- Digital devices

- Observation - Written assignments

4.0 Geometry

4.3 Similarity and Enlargement - Linear scale factor of similar figures (1)
4.3 Similarity and Enlargement - Linear scale factor of similar figures (2)

By the end of the lesson, the learner should be able to:
- Define linear scale factor
- Calculate linear scale factor from similar figures and use it to find unknown lengths
- Show interest in applying linear scale factor to practical situations

The learner is guided to:
- Measure corresponding sides of similar figures
- Calculate ratios to find linear scale factor
- Use scale factor to determine unknown dimensions
- Apply to practical situations

What is linear scale factor?

- Master Mathematics Grade 9 pg. 200
- Rulers
- Similar objects
- Calculators
- Models
- Maps
- Scale models
- Real objects

- Observation - Oral questions

4.0 Geometry

4.4 Trigonometry - Angles and sides of right-angled triangles
4.4 Trigonometry - Tangent ratio and tables of tangents

By the end of the lesson, the learner should be able to:
- Define hypotenuse, opposite and adjacent sides
- Identify and name sides with reference to given angles
- Show interest in recognizing right-angled triangles in real situations

The learner is guided to:
- Draw right-angled triangles
- Identify the hypotenuse
- Label opposite and adjacent sides for given angles
- Practice with different orientations of triangles

How do we identify sides of a right-angled triangle?

- Master Mathematics Grade 9 pg. 205
- Rulers
- Set squares
- Models of triangles
- Charts
- Master Mathematics Grade 9 pg. 207
- Mathematical tables
- Calculators
- Right-angled triangles

- Observation - Oral questions

4.0 Geometry

4.4 Trigonometry - Sine and cosine ratios, tables of sines and cosines

By the end of the lesson, the learner should be able to:
- Define sine and cosine of an angle
- Calculate sine and cosine ratios and read values from mathematical tables
- Develop interest in observing that cosine values decrease as angles increase

The learner is guided to:
- Work out ratios of opposite to hypotenuse (sine)
- Work out ratios of adjacent to hypotenuse (cosine)
- Read values from tables of sines and cosines
- Observe that values in cosine tables are subtracted

How are sine and cosine different from tangent?

- Master Mathematics Grade 9 pg. 211
- Mathematical tables
- Rulers
- Calculators
- Models

- Observation - Written assignments

4.0 Geometry
5.0 Data Handling and Probability
5.0 Data Handling and Probability
5.0 Data Handling and Probability

4.4 Trigonometry - Using calculators and applications of trigonometric ratios
5.1 Data Interpretation (Grouped Data) - Determining appropriate class width for grouping data
5.1 Data Interpretation (Grouped Data) - Drawing frequency distribution tables of grouped data
5.1 Data Interpretation (Grouped Data) - Identifying the modal class of grouped data

By the end of the lesson, the learner should be able to:
- Explain how to use calculators to find trigonometric ratios
- Apply trigonometric ratios to calculate unknown sides and angles
- Appreciate using trigonometry to solve real-life problems

The learner is guided to:
- Use calculator buttons for sin, cos, tan
- Find inverse trigonometric ratios
- Calculate unknown lengths in right-angled triangles
- Solve problems involving heights, distances and angles

How do we use trigonometry to solve real-life problems?

- Master Mathematics Grade 9 pg. 217
- Scientific calculators
- Rulers
- Protractors
- Real-life problem scenarios
- Master Mathematics Grade 9 pg. 224
- Writing materials
- Calculators
- Chart papers
- Digital devices
- Master Mathematics Grade 9 pg. 226
- Tally sheets
- Data sets
- Pencils
- Master Mathematics Grade 9 pg. 228
- Frequency distribution tables
- Reference materials

- Written tests - Practical activities

5.0 Data Handling and Probability

5.1 Data Interpretation (Grouped Data) - Calculating the mean of grouped data (1)
5.1 Data Interpretation (Grouped Data) - Calculating the mean of grouped data (2)
5.1 Data Interpretation (Grouped Data) - Determining the median of grouped data (1)

By the end of the lesson, the learner should be able to:
- Explain the process of finding mean of grouped data
- Calculate midpoints of classes
- Show interest in organizing data to find the mean

The learner is guided to:
- Group given data into classes
- Add class limits and divide by 2 to get midpoints
- Work out products of midpoints and frequencies (fx)
- Find the sum of fx values

How do we find the mean of grouped data?

- Master Mathematics Grade 9 pg. 230
- Calculators
- Frequency tables
- Writing materials
- Mathematical tables
- Data sets
- Charts
- Master Mathematics Grade 9 pg. 232
- Reference materials
- Digital devices

- Observation - Written tests

5.0 Data Handling and Probability

5.1 Data Interpretation (Grouped Data) - Determining the median of grouped data (2)
5.1 Data Interpretation (Grouped Data) - Determining the median of grouped data (3)
5.2 Probability - Experiments involving equally and likely outcomes

By the end of the lesson, the learner should be able to:
- Explain the formula for calculating median of grouped data
- Identify L, N, cf₁, fm and C from given data
- Appreciate the components of the median formula

The learner is guided to:
- Discuss the median formula and its components
- Identify the lower class boundary (L) of median class
- Determine cumulative frequency of class above median class
- Identify frequency of median class and class width

How do we use the median formula?

- Master Mathematics Grade 9 pg. 234
- Calculators
- Formula charts
- Frequency tables
- Master Mathematics Grade 9 pg. 236
- Data sets
- Writing materials
- Practice worksheets
- Master Mathematics Grade 9 pg. 239
- Coins
- Dice
- Triangular pyramids
- Baskets and pens

- Class activities - Oral questions - Written assignments

5.0 Data Handling and Probability

5.2 Probability - Range of probability of an event
5.2 Probability - Identifying mutually exclusive events

By the end of the lesson, the learner should be able to:
- State that the sum of all probabilities equals 1
- Determine the range of probability as 0 ≤ P(A) ≤ 1
- Show interest in understanding that P(A) + P(A') = 1

The learner is guided to:
- Toss a coin and work out probability of head and tail
- Add probabilities of all outcomes
- Use dice to determine probabilities of all faces
- Discuss that probability ranges from 0 to 1

What is the range of probability?

- Master Mathematics Grade 9 pg. 241
- Coins
- Dice
- Calculators
- Charts showing probability range
- Master Mathematics Grade 9 pg. 243
- Pictures of referees
- Real-life scenarios
- Charts

- Class activities - Written tests - Oral questions

5.0 Data Handling and Probability

5.2 Probability - Experiments of single chance involving mutually exclusive events
5.2 Probability - Experiments involving independent events

By the end of the lesson, the learner should be able to:
- Explain the addition law of probability P(A or B) = P(A) + P(B)
- Calculate probabilities of mutually exclusive events
- Show interest in applying the addition law to solve problems

The learner is guided to:
- Pick pens from a closed bag and note colors
- Work out probabilities using the word "OR"
- Apply the formula P(A or B) = P(A) + P(B)
- Solve problems involving mutually exclusive events

How do we calculate probabilities of mutually exclusive events?

- Master Mathematics Grade 9 pg. 244
- Colored pens
- Bags
- Dice
- Number cards
- Calculators
- Master Mathematics Grade 9 pg. 246
- Coins
- Colored balls
- Baskets

- Class activities - Written tests - Practical exercises

5.0 Data Handling and Probability

5.2 Probability - Drawing tree diagrams for single outcomes

By the end of the lesson, the learner should be able to:
- Explain what a tree diagram represents
- Draw tree diagrams showing probability outcomes on branches
- Show interest in verifying that sum of probabilities on branches equals 1

The learner is guided to:
- Identify possible outcomes from tossing a coin
- Draw branches and fill in outcomes
- Determine probabilities and place on branches
- Verify that sum of probabilities equals 1
- Draw tree diagrams for various probability situations

How do we represent probability using tree diagrams?

- Master Mathematics Grade 9 pg. 248
- Drawing materials
- Coins
- Calculators
- Chart papers
- Rulers

- Class activities - Written tests - Practical activities