Question

Area of circular field is 13.86 hectares. The cost of fencing it at the rate of 20 paise per meter

Answer 1

πr2=13.86
22/7×r2=13.86
1/7×r2=63
R2=7×3×3×7
R=21
1m=₹20/100
2πr=2×22/7×21=132m
1m=₹1/50
Cost of fencing =1/50×132?=₹2.64

Answer 2

Given:

Area of circular field is 13.86 hectares

To Find:

Find the cost of fencing it at the rate of 20 paise per meter

Solution:

Area of circular field = $\pi r^2$

Area of circular field = 13.86 hectares  

1 hectare = 10000 sq.m.

13.86 hectares = $13.86 \times 10000=138600 sq.m.$

So, Area of circular field in sq.m. = 138600 sq.m.  

So,$\pi r^2 =138600\\\frac{22}{7} \times r^2 = 138600\\r^2=138600 \times \frac{7}{22}\\r=\sqrt{138600 \times \frac{7}{22}}\\r=210 m$

Circumference of field =$2 \pi r = 2 \times \frac{22}{7} \times 210=1320 m$

Cost of fencing 1 m= 20 paisa  

Cost of fencing 1320 m =$1320 \times 20 =26400 paisa$

100 paisa = 1 rupee

26400 paisa = $\frac{26400}{100}=Rs.264$

Hence The cost of fencing is Rs.264