Question

If the difference between outer and inner radii of a circular ring is 14 cm, then the difference between outer and inner circumferences, is ______.

Answer 1

If the difference between outer and inner radii of a circular ring is 14 cm, then the difference between outer and inner circumferences, is 88 cm.

Explanation:

Let outer and inner radii be R and r with R – r = 14.

Difference of circumferences = 2πR – 2πr

= 2π(R – r)

= 2π·14

= 28π cm   ...(= 88 cm if π = `22/7`, ≈ 87.96 cm if π ≈ 3.1416)