A field is in the form of a circle. The cost of fencing around it at ₹12 per metre is ₹2,640. What is the area (in m$^2$) of the field? (Take $\pi = \frac{22}{7}$)
Answer & explanation
Correct answer: option 1
We know that,
Area of circle = πr2
Perimeter of circle = 2πr
Cost of 1 m fencing = Rs. 12 per metre
Total length of fencing = \(\frac{2640}{12}\) = 220 m
Perimeter of circle = 220
Now according to the question,
2πr = 220
2 × \(\frac{22}{7}\) × r = 220
r = 35
Area of circle = πr2 = \(\frac{22}{7}\) × 35 × 35 = 3850 m2