How_To_Be_Good_At_Math

226 GEOMETRY • PRISMS

Prisms

A prism is a special kind of 3D shape. It is a polyhedron, which

means that all its faces are flat. Its two ends are also the same

shape and size, and they are parallel to each other.

Cross sections

If you cut through a prism

parallel to one of its ends,

the new face you make is

called a cross section. It

will be the same shape

and size as the original

flat face.

The tent shape’s

ends are parallel

triangles, so we call

it a triangular prism

All cross sections

will be the same

size and shape

The marshmallow

is a prism – its

parallel ends

are squares

Finding prisms

Look at this picture of a

campsite. We’ve pointed out

some prisms, but can you

spot them all? You should

be able to find eight.

A prism is the same size

and shape all the way

along its length.

226_227_3D_Prisms.indd 226 29/02/2016 18:05