Q17 of 47 Page 1

In the given figure, two concentric circles with center O have radii 21 cm and 42 cm. If , find the area of the shaded region. [Use =]

Required area = area of outer circle - area of inner circle - (area of sector OAB - area of OCD)


Given, radius of outer circle, R = 42 cm


Radius of inner circle, r = 21 cm


Angle of sector, θ = ∠AOB = ∠COD = 60°


Also, area of a circle with radius 'r' is πr2


area of a sector with angle θ and radius r is


Using formulas,


Required area


Putting values,






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