A spherical balloon is inflating with helium at a rate of 300x min How fast is the balloon's radius increasing at the instant the radius is 5 ft? View by Day Write an equation relating the volume of a sphere, V, and the radius of the sphere, r. (Type an exact answer, using it as needed ) Differentiate both sides of the equation with respect to t. dV dr dt (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 of at the instant the radius is 5 ft. (Simplify your answer.) ft f12/ min fts / min ft / min Next