Question

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

Answer 1

Radius of circle (r) = 21 cm

𝜃 = angle subtended at centre = 120°

Length of its arc =`theta/360^@`× 2𝜋𝑟

=`120/360× 2 ×22/7× 21`

= 44 cms

Area of sector =`theta/360^@× pir^2`

=`120/360×22/7`× 21 × 21

= (22 × 21)

= 462 cm²

𝐿𝑒𝑛𝑔𝑡ℎ 𝑜𝑓 𝑎𝑟𝑐 = 44 𝑐𝑚

Area of sector = 462 cm²