Key learning points

1. For a triangle to be right-angled, Pythagoras' theorem must hold
2. By substituting in the three lengths, you can show whether the theorem holds
3. If the numbers produce a true statement, the triangle is right-angled
4. If they do not produce a true statement, the triangle is not right-angled

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.

Common misconception