4.1 Cuboids and Cubes
Imagine that you are going to wrap a package in paper which may not overlap. The total area of the paper is the exposed area of the packet and is called the surface area.
We say that the surface area is the area that is exposed on a geometrical body.
Cube 
The Cube’s Total Surface Area 


We call the side of the cube for s. The surface area consists of six equally large squares which you can see on the figure above. The area is calculated by first finding the area for one square and then multiplying with the number of sides of the cube (6).
Cuboids
Here below you see a cuboid. A cuboid has six sides.

You task is to calculate the surface area of the cuboid, in other words the total area of all six sides. 
If we flatten out the cuboid, we see that it looks like this:
Is it then maybe easier to calculate the area?
Surface area for a cuboid:
A + B + C + D + E + F =
9 cm^{2} + 9 cm^{2} + 15 cm^{2} + 15 cm^{2} + 15 cm^{2} + 15 cm^{2} = 78 cm^{2} 