How do you find the surface area of a cuboid?

The surface area is the total area of all the faces.

For a cuboid, all these faces will be rectangular.

Example:

Find the surface area of a 2 x 4 x 5 cm cuboid.

The area of the faces will be:

2 x 4 = 8 cm2

2 x 5 = 10 cm2

4 x 5 =20 cm2

Adding these up give an area of 38 cm2.

However we now need to multiply our answer by 2 as there are exactly two of each face.

So our final answer is 38 x 2 = 76 cm2.