3. [-/2 Points] DETAILS TANAPCALC10 6.2.060. ASK YOUR Oil Spill In calm waters, the oil spilling from the ruptured hull of a grounded tanker forms an oil slick that is circular in shape. If the radius r of the circle is increasing at the rate of 20 r'(t) = V 2t + 4 ft/min t min after the rupture occurs, find an expression for the radius at any time t. Hint: r(0) = 0. r(t) = How large is the polluted area 30 min after the rupture occurred? ft 2