I don't know what you have done so far and where you are stuck ... So here are some hints:

1. I've modified you sketch a little bi( see attachment)

2. The green-bordered triangle is congruent to the blue-bordered triangle.

3. x must be longer than 4.

4. The two colour-bordered triangles form a rhombus whose area is

5. You are dealing with a lot of right triangles. For instance:

... and now it's your turn.