He’s 12 square centimetres. So I must be half that. To calculate the area of a triangle, multiply the height by the width (this is also known as the 'base') then divide by 2. Find the area of a ...

Subtracting the 4 cm length of the square which the triangle is sitting on leaves 6 cm for the height of the triangle. Other composite shapes may have cut out sections. To work out the area of ...