## Elementary Geometry for College Students (7th Edition)

(600 - 144$\pi$) = 147.61 $ft^{2}$
The area of the rhombus whose diagonals have length d1 and d2 is given by A = $\frac{1}{2}$d1*d2 = $\frac{1}{2}$ * 30 * 40 = 600 $ft^{2}$ The area of circle whose radius is A = $\pi r^{2}$ =$\pi (12)^{2}$ =144$\pi$ The area of shaded region = area of rhombus - area of circle = (600 - 144$\pi$) = 147.61$ft^{2}$