Pythagoras' Theorem

Find missing sides in right-angled triangles using a² + b² = c², the most famous formula in geometry.

Finding a Shorter Side with Pythagoras

Rearrange Pythagoras' theorem to find one of the shorter sides of a right-angled triangle when the hypotenuse is known.
Finding the Hypotenuse

Use Pythagoras' theorem to find the longest side of a right-angled triangle when you know the two shorter sides.
Pythagoras on a Coordinate Grid

Use Pythagoras' theorem to find the straight-line distance between two points on a coordinate grid.