How do you use Pythagoras' theorem?

Pythagoras' theorem states that a² + b² = c² in a right-angled triangle, where c is the hypotenuse. To find the hypotenuse, square the two shorter sides, add, then square root. To find a shorter side, square both known sides, subtract, then square root. For example, sides of 6 cm and 8 cm give a hypotenuse of 10 cm.