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# How to Calculate the Surface Area of Different Shapes

Let’s try a practical example.

Kim wants to put clear contact all over her fish tank to protect it from scratches. Using the measurements given, calculate how much clear contact Kim will need. The important piece of information here is that the fish tank doesn’t have a lid. Now if a cube is normally six-sided, then this lidless fish tank must only be five-sided. To allow for the fact that it only has five sides, we need to address the formula.

We’ll use five L squared. The length of the fish tank is one point five meters. Substitute this into the formula. Five times one point five squared. One point five squared equals two point two five. Five times two point two five equals 11.25. The surface area of the fish tank without a lid is 11.25 meters squared. Kim will need 11.25 square meters of clear contact to completely cover the fish tank glass.

It’s important to always remember you’re dealing with square units in area, especially if you have to convert units of measurement into a different unit.