Q110 of 131 Page 226

A circular pond is surrounded by a 2 m wide circular path. If outer circumference of circular path is 44 m, find the inner circumference of the circular path. Also find area of the path.

Let R and r be the radius of the outer and inner circle respectively.


We know that the circumference of a circle =2∏r


Given, circumference of outer circle = 44 m


2∏R = 44


2 × × R = 44


R = 7 m


R = R – 2 = 7 – 2 = 5 m


Inner circumference = 2 × 3.14 × 5 = 3.14 m


Area of the path = Area of outer circle - area of inner circle


=∏R2 - ∏r2 =∏(R2 - r2)


= 3.14 (72 – 52) = 3.14 × (49 – 25) = 3.14 × 24 = 75.36 m2


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