Find the radius r of the circle if an arc of length 20 cm on

Find the radius r of the circle if an arc of length 20 cm on the circle subtends a central angle of 60°. (Round your answer to two decimal places.)

Solution

arc of length 20 cm on the circle subtends a central angle of 60°

Arc lenght = {(2pi*r)/360}*60 where r , is radius of circle

= pi*r/3

Given : pi*r/3 = 20

pi*r = 60

r = 60/pi = 19.10 cm ( radius)