Perimeter of a compound shape

A compound shape is made up of several simple 2D shapes. To calculate the perimeter, label and add up the length of each side.

Example

This shape is made from two rectangles.

What is the perimeter of this shape?

6 sided shape measuring 8 x 5 x x x y x 20 x 15m

First, calculate the missing lengths 𝑥 and 𝑦.

𝑥=20−8=12 m

𝑦=15−5=10 m

Second, label each length.

6 sided shape measuring 8 x 5 x 12 x 10 x 20 x 15m

Add up all the sides to calculate the perimeter.

8+5+12+10+20+15=70 m

Remember to make sure that all the sides have been added.