Answer:
[tex]A_s=486\ units^2[/tex]
Step-by-step explanation:
Remember that the sides of a cube always have the same length.
In this case the length of the sides L is:
[tex]L = 9[/tex].
The cubes have 6 faces. Then the surface area of the cube is equal to the area of its 6 faces.
Since all sides of the cube have the same measure, then the area of each face is:
[tex]A = L ^ 2[/tex]
Then the area of the 6 faces is:
[tex]A_s = 6L ^ 2[/tex]
[tex]A_s = 6 * (9 ^ 2)[/tex]
[tex]A_s=486\ units^2[/tex]
