Some useful formulae for areas of three dimensional objects:
Cube:

, where s is side
Rectangular box:

, where l, w, and h are length, width and height
Sphere:

, where r is radius of the sphere
Cylinder:

, where r is radius of the base and h is height
Algebra.Com is a people's math website. It relies on people, such
as yourself, who create our content. All solvers and lessons are
submitted by algebra.com's users. They retain copyright to their
content, although they do grant rights to algebra.com.