A right triangle has sides A, B, and C. Side A is the hypotenuse and side B is also a side of a rectangle. Sides A, C, and the side of the rectangle adjacent to side B have lengths of #7 #, #4 #, and #9 #, respectively. What is the rectangle's area?
This is what I am imagining the your problem looks like, based on the information you gave.
First, use the pythagorean theorem to find side B:
Then find the area of the rectangle: