2. Prisms
A prism is a solid object with:
identical ends
flat faces
and the same cross section all along its length !
Try drawing a shape on a piece of
paper (using straight lines)
Then imagine it extending up from the sheet of paper ...
... that's a prism !
No Curves!
A prism is a polyhedron, which means all faces are flat! No curved sides.
For example, a cylinder is not a prism, because it has curved sides.
3. Bases
The ends of a prism are parallel
and each one is called a base.
Sides
The side faces of a prism are parallelograms
(4-sided shapes with opposite sides parallel)
These are all Prisms:
Square Prism: Cross-Section:
Cube: Cross-Section:
4. (yes, a cube is a prism, because it is a square
all along its length)
(Also see Rectangular Prisms )
Triangular Prism: Cross-Section:
Pentagonal Prism: Cross-Section:
and more!
Regular and Irregular Prisms
All the previous examples are Regular Prisms, because the cross section is regular (in other
words it is a shape with equal edge lengths, and equal angles.)
Here is an example of an Irregular Prism:
Irregular Pentagonal Prism:
Cross-Section
It is "irregular" because the
cross-section is not "regular" in shape.
5. Surface Area of a Prism
Surface Area = 2 × Base Area
+ Base Perimeter × Length
Volume of a Prism
The Volume of a prism is the area of one end times the length of the prism.
Volume = Base Area × Length
