Question

Find the difference of the areas of a sector of angle 120° and its corresponding major sector of a circle of radius 21 cm.

Answer 1

As given angle of one sector = 120°
So,angle of other sector = 360° - 120° = 240°
So,difference of areas of two sectors of angles 240° and 120° is :

$\frac{240}{360} \times \frac{22}{7} \times 21 \times 21 - \frac{120}{360} \times \frac{22}{7} \times 21 \times 21$

$= 924 - 462 = 462 \: m {}^{2}$