Question
The area of a circular field is 13.86 hectares. Find the
cost of fencing it at the rate of Rs. 4.40 per metre.Solution
By using the above formula, the area of the field ⇒ πr2 = 13.86 × 10000 ⇒ (22/7)r2 = 138600 ⇒ r2 = (7/22) × 138600 ⇒ r2 = 44100 ⇒ r = 210 m Length of circular field = 2πr Length of circular field = 2 × (22/7) × 210 = 1320 m. Hence, the cost of fencing it at the rate of Rs. 4.40 per meter ⇒ 1320 × 4.4 = 5808 ∴ The cost of fencing is Rs. 5808.
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