Question

Find the area of the circular ring formed by two concentric circles, given that the radii of the outer and the inner circles are $4$ cm and $2$ cm respectively

• A. $75.33$ sq. cm
• B. $12.36$ sq. cm
• C. $23.47$ sq. cm
• D. $37.68$ sq. cm

Answer 1

Answer: (D)

$37.68$ sq. cm

The area of the region enclosed by two concentric circles is given by

$A=\pi (R^2–r^2)$

Here, $R=4cm$, $r=2cm$ and $\pi$ = 3.14

So Area, $A=3.14(16–4)sqcm$ = $3.14\left(12\right)sqcm=37.68sq.cm$.

Therefore option D is the answer.