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