Surface area of prisms - 17th Sep 2008
We looked at how to find the surface area of prisms.
There is a lesson on Mymaths explaining how to calculate the surface area of prisms by thinking about the shape of their nets. We concentrated on cuboids and triangular prisms. We will look at cylinders in a future lesson.
To find the total surface area of any prism you have to find the area of each individual face of the shape and then add them together.
For example, to work out the surface area of this cuboid with sides of length 3, 4 & 5.
We can think of the cuboid as a net.
Then work out the area of each face (remember that on a cuboid opposite faces are equal)
4 x 5 = 20
4 x 5 = 20
4 x 3 = 12
4 x 3 = 12
3 x 5 = 15
3 x 5 = 15
To find the total surface area just add the areas together
20 + 20 + 12 + 12 + 15 + 15 = 94
The surface area of a triangular prism is done in the same way, but remember that the area of a triangle = ½ base x height
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