Q4 of 35 Page 311

The cost of fencing of our village play ground with railing is Rs. 924 at the rate of Rs. 21 per meter. Let us write by calculating how much sq. meter canvas will be bought for covering the field.

Given, the cost of fencing = Rs 924


Now cost of fencing = perimeter of playground × rate of fencing ground per meter


⇒ 924 = perimeter × 21


⇒


= 44 m


But, Perimeter = 2πr where r is the radius of the play ground


⇒


= 7 m


Canvas required will be calculated by calculating the area of the circular field


Area of circular field = πr2 where r is the radius of the play ground


⇒


⇒ 154 m2


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