# 8.10.2. Converse of Pythagoras Theorem

In the figure below,

- A
- B
- C
- D

### Example

In the figure below,

### Solution

Step 1: Establish that

The converse of pythagoras' theorem states that if the square of the length of a side is equal to the sum of the squares of the other two sides,
then the angle opposite to this side is a right angle. For

Since

Since

Step 2: Find the parallelogram's area.

Since opposite sides of a parallelogram are equal in length, then

Use the formula for the area of a parallelogram, with