Question

ABCD is a flower bed of OA = 21 m and OC = 14 m. Find the area of the bed (take $\pi$ = 22/7)

• A. $192.5m^2$
• B. $188.5m^2$
• C. $388.5m^2$
• D. $288.5m^2$

Answer 1

Answer: (A)

$192.5m^2$

We have ,
$OA=R=21m$ and $OC=r=14m$

$\therefore$ Area of the flower bed

= Area of A quadrant of a circle of radius R - Area of a quadrant of a circle of radius r

$=\frac{1}{4}\pi R^2-\frac{1}{4}\pi r^2$

$=\frac{\pi }{4}(R^2-r^2)$

$=\frac{1}{4}\times \frac{22}{7}({21}^2-{14}^2)c{m}^2$ .......[$\because$ $R=21m$ and $r=14m$]

Area of the flower bed $=[\frac{1}{4}\times \frac{22}{7}(21+14\left)\right(21-14\left)\right]m^2=[\frac{1}{4}\times \frac{22}{7}35\times 7]m^2=192.5m^2$