A stone is dropped into a lake, creating a circular ripple that travels outward at a speed of 20 cm/s. Find the rate at which the area within the circle is increasing after:

(a) 1 s
(b) 3 s
(c) 5 s
(What can can you conclude?)

(a) sq cm/sec
(b) sq cm/sec
(c) sq cm/sec

You can earn partial credit on this problem.