Question

In given figure, $AB$ and $CD$ are two diameters of a circle perpendicular to each other and $OD$ is the diameter of the smaller circle. If $OA=7$, find the area of shaded region.

Answer 1

Area of shaded region$=$Area of big circle$-$area of small circle

$=\pi R^2-\pi r^2=\pi (R^2-r^2)$

$=\frac{22}{7}(7^2-{\left(\frac{7}{2}\right)}^2)$

$=\frac{22}{7}(49-12.25)=\frac{22}{7}\times 36.75$

$=115.5c{m}^2$