## Book: RS Aggarwal - Mathematics

### Chapter: 18. Area of Circle, Sector and Segment

#### Subject: Maths - Class 10th

##### Q. No. 46 of Exercise 18A

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46
##### The cost of fencing a circular field at the rate of Rs. 25 per meter is Rs. 5500. The field is to be ploughed at the rate of 50 paise per m2. Find the cost of ploughing the field. [Take π = 22/7]

Given:

Rate of fencing a circular field = Rs. 25/m

Cost of fencing a circular field = Rs. 5500

Rate of ploughing the field = 50p/m2 = Rs. 0.5/m2

Let the radius of circular field be ‘r’ and the length of the field fenced be ‘x’ m.

Then, 25 × x = 5500

x = = 220 m

Circumference of circular field = 2πr

220 = 2πr

220 = 2 × × r

r =

r = 35 m

Area of the circular field = πr2

= × 35 × 35

= 22 × 5 × 35

= 3850m2

Now, cost of ploughing the field = Rate of ploughing the field × Area of the field = 0.5 × 3850

= Rs. 1925

Hence, the cost of Ploughing the field is Rs. 1925.

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