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.

Area = (13.86 x 10000) sq.m = 138600 sq.m

$\mathrm{\pi R}2=138600\Rightarrow R2=138600\times \frac{7}{22}\Rightarrow R=210m$ 

Circumference =  $2\mathrm{\pi R}2=2\times \frac{22}{7}\times 210=1320m$ 

Cost of fencing = Rs. (1320 x 4.40) = Rs. 5808.