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9-2A Volume of Prisms
What is volume?
What question must you ask before you
can begin finding the volume of a prism?
Definition
His mom yelled at him to turn the volume
down on his playstation.
The volume of the bottle was two liters.
The volume of a solid is the number of
cubic units contained in the solid.
Volume measures how much a solid can
“hold”.
Count Up the Volume
1.
2.
3.
4.
Find the volume of the right
rectangular prism.
Write a formula for finding
the volume of a right
rectangular prism.
What is the area of a
rectangle?
How does the shape of the
base work into the volume
formula?
w
l
H
V=l·w·H
Find the Volume
1.
2.
3.
Ask: What is the
shape of the base?
V=lwH
V = (8)(3.6)(4.5)
4.5 in
3.6 in
129.6 in3
8 in
Find the Volume
1.
2.
3.
What is the shape of
the base?
V=½bhH
V = ½ (43)(68)(29)
V = 42,398 mm3
29 mm
68 mm
43 mm
Cavalieri’s Principle
Turn to page 626 in your book.
Cavalieri’s principle states that if two prisms have
the same base area and the same height, then
they will have the same volume.
That means whether you have a right prism or an
oblique prism, the volume will be the same.
Theorem
The volume of a right rectangular prism is
the product of its length, width, and
height.
V=lwH
H
w
l
Theorem
The volume of any prism is the product of
the area of its base and its height.
V=bH
We will be working with prisms with square,
rectangular and triangular bases.
Ask: What is the shape of the base?
Assignment 9-2A
Page 628, 11-12, 27-28
and worksheet
NO FORMULAS WITH NUMBERS
NO CREDIT