In the diagram, O is the center of a circle with radii OP=OQ=5. What is the perimeter of the shaded region?
arc OP has the length 2pi (5) (60 /360) = (10/6) pi = (5/3)pi
So the perimeter is
(5/3) pi + 5 + 5 =
10 + 5pi / 3 = (30 + 5pi) / 3
