Question

Two concentric circle are of radii 7 cm and 5 cm. Find the area of the portion between two circles.

Answer 1

Area $=\pi [R^2-r^2]$

$=\pi [7^2-5^2]$

$=\pi (7-5)(7+5)$

$=24\pi$

$=75.43c{m}^2$.