Key Idea: Surface Area

Surface area is the total area of all the faces (or surfaces) of a 3D figure.

General Rule:

Surface Area = Sum of the areas of all faces

• For prisms and pyramids: add the areas of all flat faces.

• For cylinders and cones: include curved surfaces plus bases.

Why this matters for the SAT:

Surface area problems appear in 3D geometry questions.
Knowing how to sum all individual areas lets you calculate the total material needed to cover a shape.