Question

A circular park encloses an area 5544 sqm .Find the cost of fencing the park at the rate of rupees 20 per metre.

Answer 1

First of all, the two formulas we should keep in mind are as follows :

(A) Area of circle : πr²

(B) Perimeter of circle : 2πr

So, let the radius of the circle be "r". Then, according to the question,

Area = πr² = 5544

Or, (22×r²)/7 = 5544

Or, r² = 1764

Or, r = √1764 or 42 metre.

Now, perimeter = 2πr

Or, perimeter = (44/7)×42

Or, perimeter = 264 metre.

Given, 1 metre fencing cost = Rs. 20

So, 264 metre fencing cost = Rs.(20×264) = Rs. 5280 [ANS.]

Answer 2

Your Answer:

Area : 5544 m²

Area of circle = 5544

πr² = 5544

r² = 5544*1/π

r² = 5544 * 7/22

r² = 1764

r = √1764

r = 42

Now, fencing is always done in outer area that is circumference of a circle

So,

Circumference = 2πr

= 2*22/7*42

= 44*6

= 264

cost of fencing the park at the rate of rupees 20 per metre

= ₹ 264 * 20

= ₹ 5280