In these lessons, we will learn
A cube is a three-dimensional figure with six equal square faces. The surface area of a cube is the sum of the area of the six squares that cover it.
The figure above shows a cube. The dotted lines indicate edges hidden from your view.
If s is the length of one of its sides, then the area of one face of the cube is s2.
Since a cube has six faces the surface area of a cube is six times the area of one face.
Surface area of a cube = 6s2
Find the surface area of a cube with a side of length 3 cm
Given that s = 3
Surface area of a cube = 6s2 = 6(3)2 = 54 cm2
The following videos show how to find the surface area of a cube.
This video shows how to find the length of a cube given the surface area.
Another way to look at the surface area of a cube is to consider a net of the cube. The net is a 2-dimensional figure that can be folded to form a 3-dimensional object.
Imagine making cuts along some edges of a cube and opening it up to form a plane figure. The plane figure is called the net of the cube.
The following net can be folded along the dotted lines to form a cube.
We can then calculate the area of each square in the net and then multiply the area by 6 to get the surface area of the cube.
There are altogether 11 possible nets for a cube as shown in the following figures. Notice that the surface area of each of the net is the same.
This video shows how to use nets and 3-dimensional figures to find surface area of cubes and prisms.