# Describe the relationship between scale factors and perimeters of two shapes

I can describe the relationship between scale factors and side lengths and perimeters of two shapes.

# Describe the relationship between scale factors and perimeters of two shapes

I can describe the relationship between scale factors and side lengths and perimeters of two shapes.

## Lesson details

### Key learning points

- If the lengths of the sides of a shape have been doubled, the perimeter will be double.
- If the side lengths of a shape are multiplied by the same factor the perimeter will be multiplied by the same factor.
- The number which all the sides have been multiplied by is called a scale factor.

### Common misconception

Pupils may remember to scale one of the sides (or pairs of sides) of a shape but forget to scale the others.

Focus attention on what it means when a shape is similar, drawing on examples and non-examples to support learners to understand how scaling affects all side lengths.

### Keywords

Perimeter - Perimeter is the distance around a two-dimensional shape.

Scale factor - A scale factor is the multiplier between similar shapes that describes how large one shape is compared to the other.

Similar - Two shapes are similar when one shape can become the other after a resize, flip, slide or turn.

### Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

## Video

Loading...

## Starter quiz

### 6 Questions

Change something

Make something larger

Make something smaller

30

28

24

27