The area of this composite figure is 533 square inches. The formula for a rectangle is lw, and the formula for the area of a triangle is 1/2bh. After plugging the values into these formulas, we have to add the values all together to get the final area.
A = L * W = 75 so L = 75/W Cost = 4W + 8(2L + W) = 4W + 16L + 8W = 12W + 16L = 12W + 1200/W C' = (12(W^2 - 100))/(W^2) = (12(W-10)(W+10))/(W^2) so W = 10 then L = 7.5