VIDEO: Calculate the lateral surface of the cuboid

Use individual areas of the cuboid

The lateral surface of a cuboid is the entire surface of the body.

1. In order to be able to determine the surface area of ​​a cuboid, you can first calculate all areas individually and then add them together.
2. Imagine the cuboid unfolded and two-dimensional.
3. Now you determine the individual areas by multiplying the length by the width.
4. Since you can see that two surfaces correspond to each other, you only need to calculate three surfaces.


Calculate the mass of a cuboid - this is how it works

If you have a cuboid, you can't just weigh it to determine its weight. …

5. Add the three values ​​together and then take two times to determine the surface area of ​​the cuboid.

From this calculation you can see that the surface area = 2 * (a * c + b * c + a * b). a and b are each length and width, while c is the height of the cuboid. You can memorize this formula, or you can use the individual areas to derive it whenever you need it.

Calculation example for the outer surface

• For a calculation example, assume that your cuboid is 7 cm long, 5 cm wide and 3 cm high.
instagram viewer
• Unfolded, calculate the three individual areas as: 7cm * 5cm = 35cm², 3cm * 5cm = 15cm², 7cm * 3cm = 21cm².
• Adding it results in 35cm² + 15cm² + 21cm² = 71cm².
• Now double the result, since each area appears twice, i.e. 2 * 71 cm² = 142 cm². The outer surface of your cuboid is 142 square centimeters.
• Alternatively, you can also use the formula that you derived from the calculation.
• The result for the surface area is: 2 * (7cm * 3cm + 5cm * 3cm + 7cm * 5cm) = 142 cm².