Question

Find the area of the shaded portions. Round answers to the tenths place if necessary.

Please help me, people!!

Answer 1

12.56 square cm

Explanation:

Radius of bigger semicircle R= 4 cm

Radius of one smaller semicircle r = 2 cm

Area of shaded portion = Area of bigger semicircle - 2 times area of one smaller semicircle.

`= (1)/(2) \pi {R}^(2) - 2 * (1)/(2) \pi {r}^(2) \\ \\ = (1)/(2) \pi {R}^(2) - \pi {r}^(2) \\ \\ = \pi( (1)/(2) * {R}^(2) - {r}^(2)) \\ \\ = \pi( (1)/(2) * {4}^(2) - {2}^(2) ) \\ \\ = \pi( (1)/(2) * 16 - 4) \\ \\ = \pi(8 - 4) \\ = 3.14 * 4 \\ = 12.56 \: {cm}^(2) \\`