Question

The area of sector AOB is 20.25 pi ft ^2 . Find the exact area of the shaded region.

Answer 1

Remark

If you have the area of the sector, then what you need is the area of the triangle in order to find the area of the shaded area. Just subtract the two.

Area of the triangle

The right angle makes finding the base and height very easy since they are equal

Area_Triangle = 1/2 * b * h

b = 9

h = 9

Area = 1/2 * 9 * 9

Area = 1/2 * 81

Area = 40.5

Area of the Shaded Area

Area_shaded = area of the sector - area of the triangle.

Area_shaded = 20.25 * pi - 40.5

Area_shaded = 20.25(pi - 2) <<<< Answer