In the diagram above, O is the center if the two concentric circle of radii 13cm and 10cm respectively. Find the area of the shaded portion in the sector with angle 1200 at the center
-
A.
(frac{1}{3}pi cm^2) -
B.
(pi cm^2) -
C.
(3pi cm^2) -
D.
(23pi cm^2) -
E.
(46pi cm^2)
Correct Answer: Option D
Explanation
(frac{120pi}{360}(R^2 – r^2)\
frac{1}{3}times pi (13^2 – 10^2)\
frac{1}{3}times pi times 69 = 23pi cm^2)