MJ2A
Ch 11.3 – Volume: Pyramids and Cones
Bellwork
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Calculate volume
6m
10 m
3m
6 in
12 in
Assignment Review
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Text p. 566 # 11 – 16
Before we begin
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Please take out your notebook and get ready to
work…
In the last lesson we looked at how to calculate the
volume of prisms and cylinders…
In today’s lesson we will continue to look at
volume…this time of pyramids and cones
Objective 11.3
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Students will find the volume of pyramids and
cones.
Volume
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As with the calculation of the volume of prisms
and cylinders you will continue to use the
formula method to calculate the volume of
pyramids and cones.
The formula method is:
1.
2.
3.
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Write the formula
Substitute
Do the math
Let’s look at an example with a pyramid…
Volume of a Pyramid
V = 1/3 Bh
V = 1/3 (15 x 15) 12
V = 1/3 (225) 12
V = 1/3 (2700)
V = 900 in 3
12 in
Note: The “B”
represent (l x w)
15 in
15 in
Your Turn
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In the notes section of your notes use the formula
method to calculate the volume of:
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A pyramid with a base of 4ft x 4ft and a height of
6 ft
Volume of a Cone
5 cm
4 cm
3 cm
V = 1/3 πr2h
V = 1/3(3.14)(3)2(4)
V = 1/3(3.14)(9)(4)
V = 1/3 (3.14)(36)
V = 1/3(113.04)
V = 37.68 cm3
Comments
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Be careful here…as you can see the formula’s are
getting more complex.
It’s important for you to re-write the entire
equation as you work each step.
Student’s that do not re-write the equation as they
work it usually skip a step and wind up getting the
incorrect answer.
Summary
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In the notes section of your notebook summarize
the key concepts covered in today’s lesson
Today we discussed
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Volume of pyramids and cones
What method is used to calculate the volume?
Assignment
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Text p. 571 # 10 – 20
This assignment is due today
Make sure that you are using the formula method
Show all work (no work = no credit)