1. Click the mouse button or press the Space Bar to display the answers.
Transparency 6

2. Splash Screen

3. Find the volumes of pyramids and cones
Objective
Find the volumes of pyramids and cones
Volume of pyramid
Volume of cone
Example 6-3b

4. A three-dimensional figure with one circular base
Vocabulary
Cone
A three-dimensional figure with one circular base
Example 6-3b

5. Vocabulary
Pyramid
A polyhedron with one base that is a polygon and faces that are triangles
Example 6-3b

6. Example 1 Find the Volume of a Pyramid
Example 2 Use Volume to Solve a Problem
Example 3 Find the Volume of a Cone
Lesson 6 Contents

7. Find the volume of the pyramid.
Volume = (Area of base)  Height of Pyramid
Volume = (L  W)  Height of Pyramid
Replace formula for rectangle in “area of base”
Volume = (7 cm
 3 cm)
 20 cm
Replace L with 7 cm
Replace W with 3 cm
Replace Height of Pyramid with 20 cm
1/3
Example 6-1a

8. Find the volume of the pyramid.
Volume = (Area of base)  Height of Pyramid
Volume = (L  W)  Height of Pyramid
Volume = (7 cm
 3 cm)
 20 cm
Since multiplication is the only process, multiply all numbers
Answer:
Volume = 140
cm3
Multiply the units of measure
1/3
Example 6-1a

9. Find the volume of the pyramid.
Answer:
Volume = 80 m3
1/3
Example 6-1b

10. Write formula for volume of a pyramid
SOUVENIRS A novelty souvenir company wants to make snow “globes” shaped like a pyramid. It decides that the most cost-effective maximum volume of water for the pyramids is 12 cubic inches. If a pyramid globe measures 4 inches in height, find the area of its base.
V = Bh
Write formula for volume of a pyramid
12 in3 =
 B
 4 in
Replace V with 12 in3
Define variable as B which is area of base
Replace h with 4 in
2/3
Example 6-2a

11. Ask “What is being done to the variable?”
V = Bh
2 things: Multiplied by 4 and
12 in3 =  B  4 in
Do the inverse of one at a time
12 in3 =  B  4 in
Bring down entire equation
4 in
4 in
Using a fraction bar, divide both sides by 4 in
3 in2
=  B
Combine “like” terms
2/3
Example 6-2a

12. Ask “What is being done to the variable?”
Do the inverse of one at a time
3 in2
=  B
Bring down entire equation
Using a fraction bar, divide both sides by
Answer:
9 in2
= B
Combine “like” terms
Remember: B = Area of Base!
2/3
Example 6-2a

13. TOYS A company is designing pyramid shaped building blocks with a square base. They want the volume of the blocks to be 18 cubic inches. If the length of the side of the base is 3 inches, what should be the height of the blocks?
Answer: H = 6 in.
2/3
Example 6-2c

14. Find the volume of the cone. Round to the nearest hundredth.
Write formula for area of cone
(1.5 m)2
 8 m
Replace r with 1.5 m
2.25 m2
 8 m
Replace h with 8 m
Follow order of operations
P E MD AS
Evaluate the exponent
3/3
Example 6-3a

15. Find the volume of the cone. Round to the nearest hundredth.
Since multiplication is the only process, multiply all numbers
(1.5 m)2
 8 m
2.25 m2
 8 m
Multiply the units
Answer:
V = m3
3/3
Example 6-3a

16. Find the volume of the cone. Round to the nearest hundredth.*
Find the volume of the cone. Round to the nearest hundredth.
Answer:
V = in3
3/3
Example 6-3b

17. Volume of Pyramids and Cones
Assignment
Lesson 7:6
Volume of Pyramids and Cones
All
End of Lesson 6