Introduction to prisms and volume

1. PRISMS
• A prism is a solid with a constant cross section
in one direction. The cross section has the
same shape as the base.

2. PRISMS
It doesn't matter
which way a
prism is facing, (or
which of its faces is on the
bottom), we always
refer to the cross
sectional shape is
“the base”.

3. THE CHEESE TEST
• To test whether an object has a constant cross
section, we start taking slices from the base, all the
way to the top.
If all the slices are the same size and shape – it’s a
prism!

4. THE CHEESE TEST
PRISM
(if we slice this block the right
way, all these slices will be the
same)
NOT A PRISM
(the shape of these slices will
change, no matter which way you slice
it)

5. THE CHEESE TEST
NOT A PRISM
(if we slice this cone, every slice
will be a different size…)
PRISM
(this cylinder can be sliced so that
every slice is the same size and shape)

6. LAYERS
• We can imagine that every prism is build up of
layers: Slices that are one unit high.
BASE LAYER:
Area = 8 units2
Height = 6 units
(6 layers)
What would the volume of this prism be?

7. LAYERS
• What is the base area of each of these
prisms?
• How many layers are there in each?
• How could we find the Volume?

8. WHICH OF THESE SOLIDS ARE PRISMS?

9. You’re ready to take on the ACE OF BASE QUIZ in lesson 3…