Surface area of a cube
To derive the formula of the surface area of a cube, you will need to start with a cube as shown below and call the length of one side a.
In order to make a cube like the one shown above, you basically use the following cube template:
Looking at the cube template, it is easy to see that the cube has six sides and each side is a square
The area of one square is a × a = a
^{2}
Since there are six sides, the total surface area, call it SA is:
SA = a
^{2} + a
^{2} + a
^{2} + a
^{2} + a
^{2} + a
^{2}
SA = 6 × a
^{2}
Example #1:
Find the surface area if the length of one side is 3 cm
Surface area = 6 × a
^{2}
Surface area = 6 × 3
^{2}
Surface area = 6 × 3 × 3
Surface area = 54 cm
^{2}
Example #2:
Find the surface area if the length of one side is 5 cm
Surface area = 6 × a
^{2}
Surface area = 6 × 5
^{2}
Surface area = 6 × 5 × 5
Surface area = 150 cm
^{2}
Example #3:
Find the surface area if the length of one side is 1/2 cm
Surface area = 6 × a
^{2}
Surface area = 6 × (1/2)
^{2}
Surface area = 6 × 1/2 × 1/2
Surface area = 6 × 1/4
Surface area = 6/4 cm
^{2}
Surface area = 3/2 cm
^{2}
Surface area = 1.5 cm
^{2}

Jul 20, 17 10:41 PM
A water tank is emptied at a constant rate. Initially, 36,000 gallons of water were in the tank. A the end of five hours, 16,000 gallons remained. How
Read More
New math lessons
Your email is safe with us. We will only use it to inform you about new math lessons.