Question

the inner circumference of a circular track is 220 m. The track is 7 m wide everywhere. Calculate the cost of putting fence along the outer circle at Rs.2 per metre.

Answer 1

Inner circumference = 220

2 π r = 220

r *2* 22 = 220 * 7

r = 35 m [ inner radius ]

inner radius , r₁ = 35 m
outer radius , r₂ = 35 + 7 = 42 m

outer circumference = 2 π r ₂

= 2 * ( 22 / 7 ) * 42 = 264 m

Cost of fencing = Rs 2 ❌264 = Rs 528

Answer 2

Answer:

Given that :-

The inner circumference of a circular track is 220 m.

The track is 7 m wide everywhere.

To calculate:-

The cost of putting fence along the outer circle at Rs.2 per metre..

$\huge{\sf{\boxed{\boxed{Solution:}}}}$

Let the inner and outer radii of the circular track be r meters and R meters respectively.

Then,

Inner circumference = 220m.

$= > 2 \: \pi \: r = 220 \\ \\ 2 \times \frac{22}{7} \times r = 220 \\ \\ r = 35m$

Since , the track is 7 metre wide everywhere.

Therefore

R = outer circle = r+7 =(35 + 7)m = 42 metre.

$outer \: circumference = 2 \: \pi \: r \: \\ \\ \ = 2 \times \frac{22}{7} \times 42m = 264m$

Rate for fencing = Rs. 2 per metre .

Total cost of fencing =( Circumference × Rate )

= Rs, 264 × 2 = 528.

$\boxed{Answer:rs.\:528}$