The inner circumference of a circular track is 220m the track is 7 metre white everywhere calculate the cost of putting of a fence along the outer circle at the rate of 2 rupees per metre
Answers
Circumference of inner circle = 2πr
220 = 2*22/7*r
r=35 m
Radius of outer track = 35 + 7= 42m
Circumference of outer circle= 2πR
=2*22/7*42 = 264 m
Cost of fencing = Circumference * Rate = 264* 2 = 528 Rs.
Given:
The inner circumference of a circular track=220m
Width of track=7m
Rate of fencing=Rs.2/m
To find:
The cost of fencing the outer circle
Solution:
The cost of fencing the outer circle is Rs.528.
We can find the cost by following the steps given below-
Let us assume that the radius of the inner circle is r and the radius of the outer circle is R.
The inner circumference of the track=220m
The inner circumference of the track=2πr
So, 2πr=220
πr=110
22r/7=110
22r=770
r=770/22
r=35m
We are given that the with of the track is 7m.
The radius of the outer circle=radius of the inner circle + the with of the track
R=r+width
R=35+7
R=42m
Now, to fence the outer circle, we need to find the circumference of the outer circle.
The outer circumference of the track=2πR
=2π×42
=84×22/7
=12×22
=264m
We will use this to calculate the cost of fencing the track.
The cost of fencing the track=circumference of the outer track×rate of fencing
=264×2
=Rs.528
Therefore, the cost of fencing the outer circle is Rs.528.