Q1 of 36 Page 253

The area of a circular park is 616 m2. There is a 3.5 m wide track around the park running parallel to the boundary. Calculate the cost of fencing on the outer circle at the rate of Rs. 5 per meter.

Area of the circular park = 616 m2


width of the track = 3.5 m



Area of the circular park = 616 m2


π × r2 = 616


r2 = 196


r = √196


r = 14 m


∴ the radius of the circular park (r1) = 14 m


the radius of the park with track (r2) = 14 + 3.5


= 17.5 m


Circumference of the track = 2π (r2)


= 2× (17.5)


= 110 m


Cost of fencing per meter = Rs. 5


Cost of fencing 110 m = 110 × 5


= 550


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