Surface area of prisms

Surface area of prisms

Rectangular prisms

A prism has a uniform cross-section. When you take slices through a rectangular prism parallel to the base you get rectangles identical to the base. So the area of each slice is always the same.

Thin rectangular prism with a cross-section indicated in blue and a base indicated.


In order to find the total surface area (TSA) of a prism, we can unfold the net of the solid to reveal the individual faces, as shown in the diagram below.

Rectangular prism unfolds to a rectangular prism net. The dimensions are 3 by 4 by 5.