Please help me with this question?

A parcel delivery service will deliver a package only if the length plus girth (distance around) does not exceed 72 inches. (A) Find the dimensions of a rectangular box with square ends that satisfies the delivery service's restriction and has maximum volume. What is the maximum volume? (B) Find the dimensions (radius and height) of a cylindrical container that meets the delivery service's restriction and has maximum volume. What is the maximum volume? (A) The dimensions of the rectangular box are in. (Use a comma to separate answers as needed.)