Evaluate the area of the region.
a. 478 units^{2}
b. 578 units^{2}
c. 528 units^{2}
d. 428 units^{2}
b. Refer to the diagram to evaluate the area of the shaded region. One method is to enclose the diagram into a rectangle, and subtract the area of the unwanted regions from the area of the rectangle. The unwanted regions have been labeled A through F. The area of region A is (15)(4) = 60. The area of region B is (5)(10) = 50. The area of region C is (20)(5) = 100. The area of region D is (17)(3) = 51.
The area of region E is (20)(5) = 100. The area of region F is (10)(5) = 50. The area of the rectangle is (23)(43) = 989. The area of the shaded region is 989 - 60 - 50 - 100 - 51 - 100 - 50 = 578. If you select a, c or d, you omitted one or more of the regions A through F.