### Area of a triangle

Look at these right-angled triangles.

Move your mouse pointer over the triangles. You will see that each one is half a rectangle.

So the area of each triangle is half of its rectangle's area

This triangle is half of a rectangle which is 20cm wide and 12cm high.

area = 20cm x 12cm = 240cm^{2}

So, the area of the triangle = 240 ÷ 2 = 120cm^{2}