Question

A field is in the form of a circle. The cost of ploughing the field at Rs. 1.50 per m² is Rs. 5775. Find the cost of fencing the field at Rs. 8.50 per metre.

Answer 1

Cost of ploughing 1m² of the field = Rs1.50

The total cost of ploughing the field = Rs 5775

So,

Area of the field = The total cost of ploughing the field/Cost of ploughing per square. meter

= 5775/1.50

=3850m²

Given: A field is in the form of a circle.

Let the radius of the field = r

∴ Area of the field = πr²

⇒ 3850 = πr²

⇒ r² = 1225

⇒ r = √1225

⇒ r = √(5×5×7×7)

⇒ r = 35m

Now,

Circumference = 2πr

= 2 x 22/7 x 35

= 2 × 22 × 5

= 220 m

Cost of fencing 1m of the field = Rs 8.50

Cost of fencing 220 of the field = Rs 8.50 × 220

= Rs 1870