Right-angled triangles and the hypotenuse
Right-angled triangles and the hypotenuse

Pythagoras' theorem only works in a right-angled triangle. The hypotenuse is opposite the right angle. It is always the longest side.
Step-by-step lessons on Edexcel IGCSE Maths Pythagoras. Each one builds up to exam-style questions. Build confidence with the shared Foundation-tier content first, since roughly 40% of Higher-tier marks are targeted at the grades 4–5 boundary that both tiers have in common.