Copyright © University of Cambridge. All rights reserved.

## 'Isosceles Triangles' printed from http://nrich.maths.org/

Isosceles triangles have two equal sides.

The area of a triangle is half the base times the height.

Any of the three vertices of the triangle can be at $(20, 20)$.

There are sets of identical (congruent) triangles with an area of
$9$cm$^2$.

How many triangles are there in each set? How many sets?