The area of a rectangle is expressed the product of its length and its width. For this rectangle we are given only its width and its diagonal. Thus, we need to solve for its length. A diagonal is a line that divides the rectangle making two right triangles. We can solve its length by using the diagonal. Calculations are as follows:
cos 45 = Length / 8
Length = 4√2 in
Area = (4√2)(5) = 20√2 in
