Total cost of fencing = Rs 2640
Per meter rate of fencing = Rs 12
So,
Circumference of field = \(\frac{2640}{12}\) = 220 m
r = \(\frac{220\times7}{2\times22}\) = 35
Radius of field = 35 m
Area of field = \(\frac{22}7\times35\times35\) = 3850 m2
Cost of plugging 1 m2 field = 0.50 Rs
Total cost of plugging the field = 3850 × 0.50
= Rs 1925.00