Key learning points

1. The sum of the squares of the two shorter sides equals the square of the longest side
2. The longest side is always opposite the right angle
3. The difference between the squares of the longest and known shorter sides is the square of the remaining side
4. A calculator can perform these calculations efficiently
5. Rounding gives a less accurate answer so there might be times you wish to leave your answer with an operator

Common misconception

Keywords

• Hypotenuse - The hypotenuse is the side of a right-angled triangle which is opposite the right angle.

• Pythagoras' theorem - Pythagoras’ theorem states that the sum of the squares of the two shorter sides of a right-angled triangle is equal to the square of the hypotenuse.