A triangle is a closed shape with three sides and three vertices. The general formula to calculate the area of a triangle is half of the product of its base and height.

How do you calculate the area of a triangle? To calculate the area of a triangle, multiply the height by the width (this is also known as the 'base') then divide by 2.

A KS3 Bitesize 11-14 Maths guide showing you how to prove the area of a triangle is half base × height.