Question

A sector is cut-off from a circle of radius 21 cm. The angle of the sector is 120°. Find the length of its arc and the area.

Answer 1

Given, 

Radius of sector = 21 cm 

Angle of sector = 120° 

Length of arc = \(\frac{120°π}{180°}\times21\)

= \(\frac{2}3\times\frac{22}7\times21\) = 44 cm

Area of sector = \(\frac{θ}{360}\timesπr^2\)

= \(\frac{120}{360}\times\frac{22}7\times21\times21\)

= \(\frac{1}3\times22\times3\times21\) = 462 cm²