# Measure and calculate perimeter

## Home learning focus

Learn how to measure and calculate the perimeter of shapes in centimetres and metres.

This lesson includes:

- two videos
- two interactive activities
- one worksheet

# Learn

This video will help you to understand how to measure the perimeter of a shape. Why not make some notes as you watch the video to help you to remember later?

## Calculating perimeter

The **perimeter** is the distance all the way around the outside of a 2D shape.

To work out the perimeter, add up the lengths of all the sides.

The perimeter of the shape shown is 10 + 10 + 6 + 6 = 32

## As the crow flies

Watch up to 01:58 of this video from BBC Teach. It shows you how to calculate the perimeter of regular and irregular **polygons**. Polygons are shapes with many sides.

It also gives you a handy method to work out the missing lengths of sides. Don't forget to record the units of measurement!

# Practise

## Activity 1

**Work out the perimeter of the park**

Add together all the sides to work out the perimeter of the park.

## Activity 2

**Work out the missing lengths**

Use what you have learnt to work out the perimeter of the next park. Can you work out the lengths of the sides that are not marked?

## Activity 3

**Calculate perimeter**

Print out and complete the activity below from Twinkl to work out the perimeter of some regular and irregular polygons.

The answers can be found here.

# There's more to learn

Have a look at these other resources around the BBC and the web.