Math Help - Problems relating with mensuration.

1. Problems relating with mensuration.

Plz solve the whole question as soon as possible.

1)The circumference of a circular field is 440 m.A 10 m wide road runs around it.Find the cos of leveling the road at the rate of 14 paisa per square meter.
1 paisa = Rs100
Its the indian currency.
Or leave it where we have to find the cost.

2)A race track is in the form of a ring whose inner circumference is 440 m and the outer circumference is 506 m.Find the wedth of the track and also the area
================================================== =========

2. Originally Posted by prashantvrm
Plz solve the whole question as soon as possible.

1)The circumference of a circular field is 440 m.A 10 m wide road runs around it.Find the cos of leveling the road at the rate of 14 paisa per square meter.
1 paisa = Rs100
Its the indian currency.
Or leave it where we have to find the cost.
since the circumference is 440m, you can get the radius of the circular field by $C = 2\pi r \leftrightarrow r = \frac{C}{2\pi}$..
since the road is 10m wide, then the outer radius (including the road) is $R= r+10$

so the area of the circular road is $A_{road} = \pi R^2 - \pi r^2 = \pi (R^2 - r^2)$
i believe you can continue from here,,

Originally Posted by prashantvrm
2)A race track is in the form of a ring whose inner circumference is 440 m and the outer circumference is 506 m.Find the wedth of the track and also the area
================================================== =========
inner: $r = \frac{C_{in}}{2\pi}$
outer: $R = \frac{C_{out}}{2\pi}$

width: $R-r$
area: $\pi R^2 - \pi r^2 = \pi (R^2 - r^2)$