arc length of a sector

Question

The diagram shows a sector of a circle, radius 20cm. Angle AOB= 144 degrees, find the length of the sector please help

Answer 1

L=(q/180)(∏)(r)

L=(144/180)(∏)(20)

simplify 144/180 to 4/5

L=(4/5)(∏)(20)

20/5=4

L=16∏ cm, or

L=16*3.14159

L=50.26544 cm