(a) Find the average rate of change of the area of the circle with respect to its radius [math] as [math] changes from:
(i) 2 to 3, (ii) 2 to 2.5, (iii) 2 to 2.1

(b) Find the instantaneous rate of change when [math]. [Do you notice anything interesting about the formula of [math]?]

**Please leave all your answers in terms of "pi".**

(a) (i)