Question

the inner circumference of a circular track is 330 5he track is 10.5 m wide everywhere. calculate the cost of putting up fence along the outer circle at rate of rs 20 per metre.

Answer 1

Hey there!

Inner track's Circumference = 330 metres

2πr  = 330

⇒ 2 × 22/7 × r = 330
 
⇒ 44/7 × r = 330

⇒ r = 330 × 7/44

⇒ r = 52.5 m

Now, Radius of outer track = 52.5 + 10.5 m = 63 metres

Outer track's Circumference = 2πr

                                              = 2 × 22/7 × 63

                                              = 396  m

Therefore,
The cost of putting fence around the Outer track @ Rs.20 per m:

⇒ 396 × 20 = 7920

Hence,
The answer to your question is = Rs. 7920

HOPE IT HELPED ^_^

Answer 2

Heya !!!


This is your answer.

Given :-
Inner circumference of a circle = 330 m.
Circumference= 2πr = 330
2πr = 330
22/7 × r = 165
r = 165 × 7/22
r = 1155/22 = 52.5 m.


The track is 10.5 m wide. So, outer radius = 52.5 + 10.5 = 63 m.

therefore, circumference of outer circle = 2πr
$= 2 \times \frac{22}{7} \times 63 \\ = 18 \times 22$
= 396 m.

Cost of fencing = Rs. 20/m.

So, cost of fencing 308 m ....
= 396 × 20
= 7920

Hence, the cost of fencing is Rs. 7920.

Hope it helps ki