For the surface area of a solid, there is a similar definition, but it applies to the exterior surfaces of the solid. Surface area is the sum of all unit squares that fit on the exterior of a solid.

As the diagram below indicates, there are six surfaces to a rectangular prism. There is a front, back, top, bottom, left, and right to every rectangular prism. The surface are of a prism is nothing more than the sum of all the areas of these rectangles.

Notice that the top and bottom faces will have equal areas. The front and back faces will have equal areas. Finally, the left and right faces will have equal areas. This means instead of finding the area of all six faces, we only need to find the areas of three faces, multiply each by 2, and then find their sum.

Surface Area = Top + Bottom + Front + Back + Left + Right

Surface Area = 2 x Top + 2 x Front + 2 x Left

Surface Area = 2lw + 2lh + 2wh

Volume of Rectangular Prism

  
Volume is measured in cubic units. Two common units of volume are the cubic centimeter () and the cubic inch  ().  The volume of a rectangular prism is a measure of how much space the object takes up.

Volume is found using three dimensions: length, width, and height.

Volume of rectangular prism

Volume = l x w x h