Calculate the dimensions in feet of a cylindrical drum that

Calculate the dimensions, in feet, of a cylindrical drum that can hold 15 gal of oil with a minimum surface area

if we see in Calculation of Liquid Volume in a Horizontal Cylindrical Container

randomly i select dimensions for Cylindrical Container:

Diameter of cylinder is:4 (ft)

and Length of cylinder is:8 (ft)

and hight of cylinder is:0.20894 (ft)

then i got this volume of this cylinder is:15 gal.

Diameter of Cylinder (ft)	Length of Cylinder (ft)	Height of Liquid in Cylinder (ft)	Volume of Liquid in Cylinder (gal)
4	8	0.20894	15.0001