Question

the cost of fencing a circular field at the rate of Rs.30 per metre is Rs.6600. The field is to be ploughed at the rate of Rs.1.50 per square metre. Find the cost of ploughing the field..

Answer 1

fence of circular field = 6600/30
2*22/7*r = 220
44/7*r = 220
r = 220*7/44
r = 35
area of circular field = 22/7*35*35
= 3850*1.50
= 5775 rupee

Answer 2

Cost of fencing a circular field
= Perimeter × Rate

6600 = 2πr × 30
r = 110/π

Area to be ploughed
= area of a circle
= 2πr^2
= 2×π×110×110/π×π
= 12100 × π × 2
= 24200 π

Cost of ploughing the field
= Area of the field×Rate
= 24200π × 1.50
= 2420×15×22/7
= Rs. 114085.71