## Elementary Geometry for College Students (6th Edition)

120 $unit^{2}$
We need to find the area of the shaded region. From the diagram we can see that there are two rectangle one outer rectangle and other inner rectangle. Therefore the shaded area = Outer rectangle - inner rectangle. Area of rectangle whose base has length b and height has length h is given by A =bh. The outer rectangle has b = 30 and altitude = 20. Area of outer rectangle = B* h= 30 * 20 = 600$unit ^{2}$ Inner rectangle has base b = 24 altitude = 20 area of inner rectangle = B* h= 24 * 20 = 480$unit ^{2}$ Area of the shaded region = area of outer rectangle - area of inner rectangle. = 600 - 480 =120 $unit^{2}$