Area of a Triangle: Worked Example
22 October 2026
When your child understands the area of squares and rectangles, finding the area of a triangle is the next step. It helps to see how triangles fit into the shapes they already know.
Worked example
Find the area of a triangle with a base of 8 cm and a height of 5 cm.
First, multiply the base by the height.
8 × 5 = 40
Now, divide the answer by 2.
40 ÷ 2 = 20
The correct answer is 20 cm².
After this example, your child will spot that a triangle uses the same idea as a rectangle, but only covers half the space. They can now try similar questions to build confidence for 11+ maths and practise using methods seen on maths.com uk.
