MJ2
Ch 12.3 – Volume of Cylinders
Bellwork• Calculate the volume of the rectangular
prism. Round to the nearest 10th. Use the formula V = BhV = Bh
21.5 ft
4 ft
3.25 ft
Note: To receive full credit you must write the problem & your answer
Bellwork SolutionV = Bh
21.5 ft
4 ft
3.25 ft
V = ℓwhV = 21.5(3.25)(4)
V = 21.5(13)V = 279.5 ft2
Assignment Review
• Text p. 522 # 6 – 15
Before we begin…
• Please take out your notebook and get ready to work…
• In the last lesson we looked at the volume of rectangular prisms…
• In today’s lesson we will look at the volume of cylinders…
• We will continue to use the formula method to demonstrate what you have learned and to minimize errors…
Objective 12.3
• Students will calculate the volume of cylinders using a formula
Vocabulary
• A cylinder is a solid whose bases are congruent, parallel circles, connected with a curved side
Bases
Cylinders• You can calculate the volume of cylinders
by using the formulaV = πr2h
• The formula can be found on the FCAT reference sheet.
• Be careful here! – The formula calls for r (radius) if you are given d (diameter), you must convert it to r by dividing by 2.
Example
6 ft
20 ft
V = πr2h 1. Write the formula
2. Substitute
3. Do the math
V = 3.14(6)2(20)
V = 3.14(36)(20)V = 3.14(720)V = 2260.0 ft3
Your solution is cubed because you are measuring
3 dimensions
Your Turn
• In the notes section of your notebook draw & label the figure and then calculate volume using the formula method
30 m
18 m
Your Turn Solution• In this example you are given diameter. The formula calls
for r…so before you begin you must covert d to r by dividing 30 by 2 to get r = 15
30 m
18 m
V = πr2h
V = 3.14(15)2(18)
V = 3.14(225)(18)
V = 3.14(4050)
V = 12717 m3
Summary
• In the notes section of your notebook summarize the key concepts covered in today’s lesson.
• Today we discussed:• Volume of cylinders
• How can you tell the bases?• What methodology will you use to calculate the
volume?
Assignment
• Text p. 526 # 9 – 22
Reminder• This assignment is due tomorrow• I do not accept late assignments• Draw the figure and show how you got your
answer using the formula method