Question

A sector of a circle has a radius of 10 and area of 20π . What is the arc length of the sector ?

Answer 1

Area of sector is 1/2lr
20π=1/2×l×10
20π/5=l
4π=l

Answer 2

Area of sector = 20 pi

=> pi *r^2 (A/360) = 20 pi

=> 10^2 (A/360) = 20

=> A = 20 * 360 / 100

=> A = 72°

Now,

Length of arc = 2 pi *r (A/360)

= 2*pi * 10 * 72 /360

= 20 pi / 5

= 4 pi

Length of arc = 4 pi