Question 230498
Hello, 
First you need to find the measurement of of both sides of the rectangle then 
we can find the area. 

Use the formula A^2 + B^2 = C^2

We know the hypotenuse is 15 inches.

Let x = one side of the rectangle and x + 3 be the other side. 

Therefore: 

x^2 + (x+3)^2 = 15^2  this works out to

x^2 + x^2 + 6x + 9 = 225  combine like terms

2x^2 + 6x + 9 = 225        subtract 225 from both sides

2x^2 + 6x - 216 = 0    now we can solve x by the quadratic formula

x = 9

Therefore one side is 9 inches and the other side is 12 inches. 
Multiply these sides and the answer is:

108 square inches

You're welcome 
RJ Toftness
www.math-unlock.com