Let 
cm be the radius of the circle at time 
Rate of increase of radius of circle = 0.7 cm/sec
is positive and = 0.7 cm/sec
Let 
be the circumference of the circle.
Rate of change of circumference of circle = 
= 
= 
= 
cm/sec
The radius of a circle is increasing at the rate of 0.7 cm/s. What is the rate of its circumference?
The radius of a circle is increasing at the rate of 0.7 cm/s. What is the rate of its circumference?