Question

The radius of a circle is increasing at the rate of 0.7 cm/s. What is the rate of increase of its circumference? (0.7 cm/s​

Answer 1

Answer:

Radius increment = 0.7 cm/s

Circumference = 2πr

New circumference (after 1 second) =

     2 * π * (r + 0.7r)

= 2 * π * 1.7r

= 3.4πr

Rate of increase = 2/3.4 = 1/1.7 cm/s