Let's draw a diagram to help us visualize this cube.
A cube is a specific case of a rectangular prism. To calculate the surface area of a rectangular prism, we can use the following formula.
SA=2(l w)+2(l h)+2(wh)
Each term is multiplied by 2 because opposite faces on a rectangular prism have equal dimensions. The terms inside the parentheses represent the area of the three possible different sized faces. However, for a cube these are all the same size s. In other words l=w=h=s. We can use this fact to simplify the formula.
SA & = 2(s* s)+2(s* s)+2(s* s)
& =2s^2+2s^2+2s^2
& =6s^2
We now substitute the value of s into our formula to calculate SA.
