Question

Find the area of the shaded region:

Answer 1

Area of circle formula: A = πr²

A = π(9)²

A = 81π

A = 254.34cm²

The ratio of degrees in the shaded region to total degrees in a circle:

80/360 = 40/180 = 20/90 = 10/45 = 2/9

Multiply:

254.34/1 * 2/9

508.68/9

56.52

Therefore, the area of the shaded region is 56.52cm²

Best of Luck!

Answer 2

Find the area of the circle:

Area = PI x r^2

Area = 3.14 x 9^2

Area = 3.14 x 81

Area = 254.34 square cm

Now multiply the area of the circle by the shaded portion which is the fraction of the degree over 360 degrees:

254.34 x 80/360 = 20,347.2/360 = 56.52

The shaded area is 56.52 square cm.