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Home > Maths > Measures > Perimeter




Compound shapes

Sometimes the shape is more complicated. In this case you need to calculate 'missing' lengths and be particularly careful to include all the sides.

An L shape, with two sides measuring 2 cm, two sides measuring 3 cm, and two sides measuring 5 cm.

Perimeter = 2 + 2 + 3 + 3 + 5 + 5 = 20 cm


A plan of a play area is shown below:

Perimeter = 15 + 20 + 8 + 5 + x + y

a) Calculate the length of x and y
b) Calculate the perimeter of the play area.


a) The length of the play area is 20m, so x = 20 - 8 =12m.

The width of the play area is 15m, so y = 15 - 5 = 10m.

b) Perimeter = 8 + 5 + 12 + 10 + 20 + 15 = 70m.



Perimeter activity

Struggling to find you way around? Try this activity.



Can you conquer the elements?

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