If the length of the hypotenuse of each right-angled triangle is c and the lengths of the other two sides are a and b then the diagram on the left shows a total area of 2ab+c2 and the diagram on the right shows an area of 2ab+a2+b2 showing that a2+b2=c2. Notes and examples A simple exercise GCSE exam questions IGCSE exam questions Online maths tuition