A forest fire leaves behind an area of grass burned in an expanding circular pattern. The radius of the circle of burning grass is increasing at the rate of r(t) = 2t + 1 where t is the time in minutes. (a) Find a function that gives the area burned as a function of time. Remember, A = π r^2 (b) Find the total area burned after 5 minutes. The circumference C of a circle is a function of its radius given by C(r) = 2 π r. (a) Express the radius of the circle as a function of the circumference, r(C). (b) Find r(36π) and interpret its meaning.