Question

A circular field of radius 35 m needs 2 rounds of fence. Find the cost of fencing the field at the rate of ₹5 per meter.

Answer 1

Given :-

▪ A circular field of radius 35 m needs 2 rounds of fence.

To Find :-

▪ Cost of fencing 2 rounds of the field at the rate of ₹ 5 per meter.

Solution :-

First of all, we have to find the length of two rounds of the given circular field. which is obviously 2 times the circumference of the field.

We have, radius = 35 m, Circumference can be calculated as

⇒ Circumference = 2 × π × radius

⇒ Circumference = 2 × 22/7 × 35

⇒ Circumference = 44 × 5

⇒ Circumference = 220 m

But it is the length of only 1 round, But we have to fence 2 rounds of the field, So

⇒ Total length = 2 × 220

⇒ Total length = 440 m

Let us find the cost if the rate is ₹ 5 / m

⇒ Cost = Total length × rate

⇒ Cost = 440 × 5

⇒ Cost = ₹ 2200

Hence, The cost of fencing two rounds of the given circular field is ₹ 2200.

Answer 2

Given:

• radius= 35m
• Number of rounds = 2
• Cost of fencing per meter= Rupees 5

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Need to find:

• The cost=?

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We know,

Circumference of a circle:

$= 2 \times \pi \times r$

$= 2 \times \dfrac{22}{7} \times 35m$

$= 22 \times 2 \times 5m$

$= 220m$

Thus Circumference = 220m

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We need to have rounds of fences.

Thus the total length of fence= 2× Circumference

= 2× 220m

=440m

Given,

Cost of 1m of fence= 5 Rupees

==> Cost of 440m of fence= 440×5 rupees

==> Cost= $\red{\bold{2200\:Rupees}}$