3 it A spherical balloon is inflating with helium at a rate 0148:: ,. How fast is the balloon's radius increasing at the Instant the radius is min 2 ft? Write an equation relating the volume of a sphere. V. and the radius of the sphere, r. [1 (Type an exact answer. using 1: as needed.) Differentiate both sides of the equation with respect to t. dV dl' T Us (Type an exact answer. using it: as needed. Type an expression using r as the variable") The balloon's radius is increasing at a rate 01D '3 at the instant the radius is 2 . (Simplify your answer)