A cone of radius r and height h has volume 81π.

(a) Show that the curved surface area of the cone is given by .

(b) Find the radius and height of the cone that make the curved surface area of the cone as small as possible.

A cone of radius r and height h has volume 81π.

(a) Show that the curved surface area of the cone is given by .

(b) Find the radius and height of the cone that make the curved surface area of the cone as small as possible.