Question

The Cost of constructing a boundrt wall of a circular field is Rs. 5280 at the rate of Rs. 24 per meter. find the cost of ploughing this field at the rate of Rs. 0.50 per meter square?
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Answer 1

Given

The Cost of constructing a boundary wall of a circular field is Rs. 5280 at the rate of Rs. 24 per meter.

Find out

Find the cost of ploughing this field at the rate of Rs. 0.50 per meter square?

Solution

➟ Circumference of circle

➟ Total cost/rate

➟ 5280/24

➟ 220 m

Hence, circumference of circular field is 220m

$\rule{200}3$

✑ Circumference = 220m

➟ 2 × 22/7 × r = 220

➟ 44/7 × r = 220

➟ r = 220 × 7/44

➟ r = 5 × 7 = 35 m

✑ Area of circular boundary

➟ πr²

➟ 22/7 × 35 × 35

➟ 22 × 5 × 35

➟ 3850 m²

Hence , areas of circular boundary is 3850m²

$\rule{200}3$

✞ Cost of ploughing 1m² circular field

➟ Rs.0.50

✞ Cost of ploughing 3850m² circular field

➟ Rs.0.50 × 3850

➟ Rs.1925

Hence,

• Cost ploughing 3850m² circular field is Rs.1925

$\rule{200}3$

Answer 2

ANSWER:

Cost of ploughing the field per 3850 m² = ₹1925

GIVEN:

Cost of constructing a boundary wall = ₹5280

Cost of buliding the boundary wall per one meter = ₹24

Cost of ploughing the field per one m² = ₹0.50

TO FIND:

cost of ploughing this field at the rate of Rs. 0.50 per meter square

FORMUAE:

Area of circle = π R²

Perimeter of circle = 2 π R

Perimeter = ( Cost of constructing a boundary wall ) / ( Cost of buliding the boundary wall per one meter )

EXPLANATION:

Perimeter = 5280/24

2 π R = 220 meters

π R = 220/2

π R = 110

R = 110 / π

Area of a circle = π (110/π)(110/π)

Area of a circle = (110/π)(110

Area of a circle = 110 × 110 × 7/22

Area of a circle = 10 × 110 × 7/2

Area of a circle = 5 × 770

Area of a circle = 3850 m²

Cost of ploughing the field per 3850 m² = 3850 × 0.5

Cost of ploughing the field per 3850 m² = ₹1925