Question

The inner edge of a circular running-track is $440m$ long. If the track is $10m$ wide, find the length of the outer edge of the track.

Answer 1

$2\pi r=440m$

$r=\frac{440\times 7}{2\times 22}=70cm$ [Inner radius]

$R=r+10=80m$

$2\pi R=2\times \frac{22}{7}\times 80=502.85$m.