Originally Posted by

**Matt Westwood** Here's an idea.

Split it up into 4 triangles and a rectangle and add them all up together, like this:

First triangle: (-4, -2), (0, -2), (0, 5)

2nd tri: (0, 5), (0, 3), (9, 3)

3rd tri: (9, 3), (7, 3), (7, -3)

4th tri: (7, -4), (7, -2), (-4, -2)

Then the rectangle in the middle is (0, -2), (0, 3), (7, 3), (7, -2).

Drawing a picture again should help. It should be easy to calculate this.

Note that you have 2 pairs of triangles which are the same size, which should make the calculation even easier.