The radius of the circle, in cm, after t seconds would be 50t
The area, A, of the circle after t seconds is expressed in the equation: A = pi * r^2
A = pi * (50T)^2 = pi*2500*t^2
The change of area per unit time is obtained by differentiating the equation
A' = pi*2500*2*t A' = pi*5000*t
when t = 3 secondsA' = pi*5000*3 = 47122 cm2/s
