Y10 Foundation: Topic 25: Ratio and proportion and scale factors

Objectives:

Understand what is meant by ratio

Write a ratio in its simplest form; and find an equivalent ratio

Share a quantity in a given ratio

Understand and use examples in direct proportion

Interpret map/model scales as a ratio

Use integer and non-integer scale factors to find the length of a missing side in each of two similar shapes, given the lengths of a pair of corresponding sides

Know the relationship between linear, area and volume scale factors of similar shapes

Deduce the areas and volumes of similar shapes after they have been enlarged by simple scale factors

Read and construct scale drawing, eg work out the real distance if the map distance is 6 cm and the scale is 1:25000

Prior Knowledge:

Using the four operations

Ability to recognise common factors

Knowledge of fractions

Use ruler and compasses to construct triangles with given dimensions

Some concept of enlargement (magnification)

Key Vocabulary:

Copy and paste here.

Differentiation & Extension:

Similar triangles

Share quantities in a ratio involving fractions, and decimals

Use a map to plan a journey, eg how long will the journey take travelling at average speed of 40 km/h (or mixed speeds for different roads)

Deduce areas and volumes of similar shapes for harder scale factor enlargements (including fractions)

Further problems involving scale drawing, eg find the real distance in metres between two points on 1:40000 map

Using & Applying ideas:

Collaborate here.

NOTES

Students often work well with ratios of two quantities

They have greater difficulty with ratios of three quantities and particular attention needs to be given to this

## Y10 Foundation: Topic 25: Ratio and proportion and scale factors

## Objectives:

Prior Knowledge:## Key Vocabulary:

## Differentiation & Extension:

## Using & Applying ideas:

NOTES## Teaching & Learning Resources:

3D Shapes Resources