Question

a circular track has an inside circumference of 440m. if the width of the track is 7m. what is the outside circumference?

Answer 1

Inner circumference =
$2\pi \: r$
440=2 pi r
r=440/2 pi
r=70
Outer radius =70+7=77cm
Circumference =2 pi x 77
=484cm

Answer 2

The given inner circumference of the track is 440m. Circumference of a circle is given by 2πr where r is the radius of the circle. Now, equating them both we get inner radius as 70m. The outer radius will then be 70+7=77m. Find the circumference using the above formula. 2π(77) .Take π as 22/7. We will get 484 m as the circumference.