# The area of a circle increases at a rate of 3 cm^2 per second. Find a) how fast is the radius changing when the radius is 4 cm? b) how fast is the radius changing when the circumference is 4 cm?

Question

The area of a circle increases at a rate of 3 cm^2 per second.

Find

a) how fast is the radius changing when the radius is 4 cm?

b) how fast is the radius changing when the circumference is 4 cm?