# Pythagoras' Theorem

Do you know the lengths of two sides in a right angled triangle?

Do you need to calculate the length of the 3rd side?

You need Pythagoras' Theorem!

Pythagoras' Theorem says that, in a right angled triangle:

The square of the hypotenuse is equal to the sum of the squares on the other two sides.

We can write this more simply as : $$a^{2} = b^{2} + c^{2}$$