A circular pond is 17.5 m is of diameter. It is surrounded by a 2m wide path. Find the cost of constructing the path at the rate of ` 25 per m2?


Diameter of the circular pond = 17.5 m


Let r be the radius of the park = (17.5/2) m = 8.75 m


Given that the circular pond is surrounded by a path of width 2 m.


So, Radius of the outer circle = R = (8.75+2) m = 10.75 m


Area of the road = Area of the outer circular path – Area of the circular pond


= πr2 – πR2


= 3.14 × (10.75)2 – 3.14 × (8.75)2


= 3.14 × ((10.75)2 – (8.75)2)


= 3.14 × ((10.75 + 8.75) × (10.75 – 8.75))


= 3.14 × 19.5 × 2 = 122.46 m2


Hence, the area of the path is 122.46 m2.


Now, Cost of constructing the path per m2 = Rs. 25


cost of constructing 122.46m2 of the path = Rs. 25 × 122.46 = Rs. 3061.50


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