Enlarging triangles

Here is a triangle with a base equal to five centimetres and height equal to three centimetres. If we keep the angles the same, and then double the height and the base, we get an enlargement.

Detailed description

We can compare the areas:

Area	= \(\dfrac{1}{2}\) × base × height	Area	= \(\dfrac{1}{2}\) × base × height
	=\(\dfrac{1}{2}\) × 5 × 3		= \(\dfrac{1}{2}\) × 10 × 6
	= 7.5 cm²		= 30 cm²

When we double the height and the base of a triangle we get an enlargement that has four times the area.