Question

The figure shows two semi-circles. Find the area of the shaded part in terms of ofπ.

Answer 1

Answer:

19 sq.cm

step by step explaination:

The area of a semicircle is half of the circle. As the area of a circle is πr2. So,

the area of a semicircle = 1/2(πr^2 )

area of small semicircle= 1/2(3.14×2^2)

= 1/2(3.14×4)

=1/2(12.56)

=6.28 sq.cm

area of big semicircle= 1/2(3.14×4^2)

= 1/2(3.14×16)

=1/2(50.24)

=25.12 sq.cm

(area of shaded region=area of big semicircle - area of small semicircle)

area of shaded region=25.12-6.28

=18.84(19 sq.cm).

Answer 2

Answer:

The area of shaded part is 18.84 cm².

Step-by-step explanation:

First we need to find the area of both the semicircles.

Area of smaller semicircle = $\frac{1}{2}$ × πr² (Let us take π as 3.14)

⇒ $\frac{1}{2}$ × 3.14 × 2²

⇒ $\frac{1}{2}$ × 3.14 × 4

⇒ 3.14 × 2

⇒ 6.28 cm²

Area of smaller semicircle = 6.28 cm²

Area of bigger semicircle = $\frac{1}{2}$ × πr²

⇒ $\frac{1}{2}$ × 3.14 × 4²

⇒  $\frac{1}{2}$ × 3.14 × 16

⇒ 3.14 × 8

⇒ 25.12 cm²

Area of bigger semicircle = 25.12 cm²

Area of the shaded region = Area of Bigger Semicircle - Area of Smaller Semicircle

Area of the shaded region = 25.12 cm² - 6.28 cm²

Area of the shaded region = 18.84 cm²

Therefore, area of shaded region is 18.84 cm².