A rock is tossed into a lake and creates a ripple with a radius that increases at a rate of 20 cm/sec. The radius of the ripple can be expressed as the function R(t) = 20t, where t represents time in seconds. The area of the circle made by ripple can be expressed as
the function A(n) = Ter2, where r represents the radius in centimeters.
Which function can be used to determine the area of the ripple as a function of time?