Question

radius of a circular lawn is 4.2 km, find the cost of fencing the lawn with wire at the rate 25 paise per metre.

Answer 1

radius of circular = 4.2 km

cost fencing per m = Rs 25

Therefore since fencing is to be done around the boundary or circumference of circle . Then we must find circumference of circle by the following formula:

$circumference \: = 2\pi \: r \: (formula \: to \: calculate \: circumference)$

=> 2πr = 2 x π( 22/7 or 3.14 ) x radius(4.2)

=> 2 x 22/7 x 4.2

=> 44/7 x 4.2

=> 44 x 0.6

=> 26.4 m

So cost for fencing per m = Rs 25

So total cost = 26.4 x 25

= Rs 660 m

Hope it helps you

Answer 2

Answer: The cost of fencing the lawn is 66000 rupees.

Step-by-step explanation:

Radius of circular lawn= 4.2 km

Circumference of the circular lawn= 2pi*r

=2*22/7*42/10

=26.4km

1 km=1000m

26.4 km= 26.4*1000m= 264000m

Cost of fencing the lawn per metre= 25/100 =1/4 rupee

Cost of fencing the lawn 264000 meter= 264000*1/4 = 66000 rupees.

Hence, The cost of fencing the circular lawn is 66000 rupees.

Hope This answer helped you.