Perimeter of a rectangle = 2l + 2w
Since we know that l=5, we can say that:
2(5)=10
45-10=35 , which is the remaining perimeter aside from the 5-inch side lengths.
35=2w
w=17.5 inches
5*17.5=87.5 in^2
So, the area of the rectangle would be 87.5 in^2.