What Is Surface Area?

Student Summary

  • The surface area of a figure (in square units) is the number of unit squares it takes to cover the entire surface without gaps or overlaps.
  • If a three-dimensional figure has flat sides, the sides are called faces.
  • The surface area is the total of the areas of the faces.

For example, a rectangular prism has six faces. The surface area of the prism is the total of the areas of the six rectangular faces.

rectangular prism, length = 3 units, width = 2 units, height = 4 units.

So the surface area of a rectangular prism that has edge-lengths of 2 cm, 3 cm, and 4 cm has a surface area of

(2⋅3)+(2⋅3)+(2⋅4)+(2⋅4)+(3⋅4)+(3⋅4)\displaystyle (2\boldcdot 3)+ (2\boldcdot 3) + (2\boldcdot 4) + (2\boldcdot 4) + (3\boldcdot 4) + (3\boldcdot 4)

or 52 square centimeters.

Visual / Anchor Chart

Standards

Addressing
6.G.4

Represent three-dimensional figures using nets made up of rectangles and triangles, and use the nets to find the surface area of these figures. Apply these techniques in the context of solving real-world and mathematical problems.

Building Toward
6.G.4

Represent three-dimensional figures using nets made up of rectangles and triangles, and use the nets to find the surface area of these figures. Apply these techniques in the context of solving real-world and mathematical problems.