Question

12. Find the area of a ring shaped region enclosed
between two concentric circles of radii 20 cm
and 15 cm.​

Answer 1

$\huge\mathcal\red{Answer}$

Let us given R=20 cm & r=15 cm

The area of a ring shaped region =

$\pi \: (20) {}^{2} - \pi(15 ){}^{2} \\ (400 - 225) \times \frac{22}{7} \\ 175 \times \frac{22}{7} \\ = 550 \: sq.cm$

Answer 2

Answer:

A=π(R2﹣r2)

A≈1570.8

R Outer radius  30  

r Inner radius  20

Step-by-step explanation: