pre calculus
posted by Matt .
Environmental Concerns: The spread of oil leaking from a tanker is in the shape of a circle. If the radius r (in feet) of the spread after t hours is r(t) = 200sqrt t, find the area A of the oil slick as a function of the time t.
I don't get this at all. could someone please help me figure this out????

A = pi r^2 = pi (200√t)^2 = 40000 pi t