Question

A farmer dug a flower bed of radius 7 m at the centre of a field. He needs to

purchase fertilizer. If 1 kg of fertilizer is required for 1 square metre area ,how much

fertilizer should be purchase?
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Answer 1

Answer:

Area = Pi * (r)^2

or, A = πr^2

thus, A = 3.14159 (7)^2

which is A = 3.14159 * 49

which is 150, using appropriate significant figures (I rounded 153.97 down).

Thus, the farmer will need 150Kg.

Step-by-step explanation:

Answer 2

Answer:

Area of the circular flower bed = π r2, where r = 7 m

NCERT Solutions for Class 7 maths Integers chapter 7 img 70

Fertilizer required for the flower bed at the rate of 1 kg per 1 m2 = (154 × 1) kg = 154 kg

(ii) What will be the cost of polishing a circular table-top of radius 2 m at the rate of ₹ 10 per square meter?

Solution:

Area of the top of circular table = π r2, where r = 2 m

NCERT Solutions for Class 7 maths Integers chapter 7 img 71

Cost of polishing at the rate of ₹ 2 per sq. meter

NCERT Solutions for Class 7 maths Integers chapter 7 img 72

=₹ 25.14 (approx)

Step-by-step explanation:

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