What is Pythagoras' Theory?

Pythagoras' Theory explains that the length of sides in a right angled triangle are related. This means we can use the length of two sides to find that of the third!

The relationship he found is a² + b² = c²

Where c is the length of the longest side, a and b are the length of the shorter sides. With this equation, we can rearrange to find the length of any side.