Question

A circular park has a path of uniform width around it. The difference between the outer and inner circumferences of the circular path is 132 m. Its width is 

Options

• 20 m

•  21 m

• 22 m

• 24 m

Answer 1

Let OA = r be the radius of the inner circle and OB = r′ be the radius of the outer circle.

Therefore, circumference of the inner circle =`2pir` and circumference of the outer circle`=2pir'`

Here we have to find the width of the circular park that is we have to find `r'-r.`.

We have given the difference between the circumferences of outer circle and inner circle.

`∴ 2pir'-2pir=132`

`∴2pi(r'-r)=132`

Substituting `pi=22/7` we get,

`2xx22/7xx(r'-r)=132`

Now we will multiply both sides of the equation by `7/44`

`(r'-r)=132xx7/44`

`∴(r'-r)=3xx7`

`∴(r'-r)=21`

Therefore, the width is`21 m`.