Holt CA Course 1
10-2 Volume of Prisms and Cylinders
Warm Up
California StandardsCalifornia Standards
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Holt CA Course 1
10-2 Volume of Prisms and Cylinders
Warm Up
Find the area of each figure described. Use 3.14 for .
1. a triangle with a base of 6 feet and a height of 3 feet
2. a circle with radius 5 in.
9 ft2
78.5 in2
Holt CA Course 1
10-2 Volume of Prisms and Cylinders
MG2.1 Use formulas routinely for finding the perimeter and area of basic two-dimensional figures and the surface area and volume of basic three-dimensional figures, including rectangles, parallelograms, trapezoids, squares, triangles, circles, prisms, and cylinders. Also covered: MG2.4
California
Standards
Holt CA Course 1
10-2 Volume of Prisms and Cylinders
The volume of a three-dimensional figure is the number of cubes it can hold. Each cube represents a unit of measure called a cubic unit.
Holt CA Course 1
10-2 Volume of Prisms and Cylinders
Height
Triangular prism
Rectangular prism
Cylinder
Base
Height
Base
Height
Base
Holt CA Course 1
10-2 Volume of Prisms and Cylinders
Find the volume of each figure to the nearest tenth.
A.
Additional Example 1: Finding the Volume of Prisms and Cylinders
= 192 ft3
B = 4 • 12 = 48 ft2
V = Bh
= 48 • 4
The base is a rectangle.
Volume of a prism
Substitute for B and h.
Multiply.
Holt CA Course 1
10-2 Volume of Prisms and Cylinders
Find the volume of the figure to the nearest tenth. Use 3.14 for .
B.
= 192 602.9 in3
B = (42) = 16 in2
V = Bh
= 16 • 12
Additional Example 1: Finding the Volume of Prisms and Cylinders
The base is a circle.
Volume of a cylinder
Substitute for B and h.
Multiply.
Holt CA Course 1
10-2 Volume of Prisms and Cylinders
Find the volume of the figure to the nearest tenth. Use 3.14 for .
C.
7 ft
V = Bh
= 15 • 7
= 105 ft3
B = • 6 • 5 = 15 ft212
Additional Example 1: Finding the Volume of Prisms and Cylinders
The base is a triangle.
Volume of a prism
Substitute for B and h.
Multiply.
Holt CA Course 1
10-2 Volume of Prisms and Cylinders
Find the volume of the figure to the nearest tenth. Use 3.14 for .
A.
= 180 in3
B = 6 • 3 = 18 in.2
V = Bh
= 18 • 10
The base is a rectangle.
Volume of prism
Check It Out! Example 1
Substitute for B and h.
Multiply.
10 in.
6 in.3 in.
Holt CA Course 1
10-2 Volume of Prisms and Cylinders
Find the volume of the figure to the nearest tenth. Use 3.14 for .
B.
8 cm
15 cm
B = (82)
= 64 cm2
= (64)(15) = 960
3,014.4 cm3
Check It Out! Example 1
The base is a circle.
Volume of a cylinderV = Bh
Substitute for B and h.
Multiply.
Holt CA Course 1
10-2 Volume of Prisms and Cylinders
Find the volume of the figure to the nearest tenth.
C.
10 ft
14 ft
12 ft
= 60 ft2
= 60(14)
= 840 ft3
Check It Out! Example 1
The base is a triangle.
Volume of a prism
B = • 12 • 10 12
V = Bh
Substitute for B and h.
Multiply.
Holt CA Course 1
10-2 Volume of Prisms and Cylinders
A juice box measures 3 in. by 2 in. by 4 in. Explain whether tripling only the length, width, or height of the box would triple the amount of juice the box holds.
Additional Example 2A: Exploring the Effects of Changing Dimensions
The original box has a volume of 24 in3. You could triple the volume to 72 in3 by tripling any one of the dimensions. So tripling the length, width, or height would triple the amount of juice the box holds.
Holt CA Course 1
10-2 Volume of Prisms and Cylinders
A juice can has a radius of 2 in. and a height of 5 in. Explain whether tripling only the height of the can would have the same effect on the volume as tripling the radius.
Additional Example 2B: Exploring the Effects of Changing Dimensions
By tripling the height, you would triple the volume. By tripling the radius, you would increase the volume to 9 times the original volume.
Holt CA Course 1
10-2 Volume of Prisms and Cylinders
A box measures 5 in. by 3 in. by 7 in. Explain whether tripling only the length, width, or height of the box would triple the volume of the box.
Check It Out! Example 2A
Tripling the length would triple the volume.
V = (15)(3)(7) = 315 cm3
The original box has a volume of (5)(3)(7) = 105 cm3.
Holt CA Course 1
10-2 Volume of Prisms and Cylinders
Check It Out! Example 2A Continued
The original box has a volume of (5)(3)(7) = 105 cm3.
Tripling the height would triple the volume.
V = (5)(3)(21) = 315 cm3
Holt CA Course 1
10-2 Volume of Prisms and Cylinders
Check It Out! Example 2A Continued
Tripling the width would triple the volume.
V = (5)(9)(7) = 315 cm3
The original box has a volume of (5)(3)(7) = 105 cm3.
Holt CA Course 1
10-2 Volume of Prisms and Cylinders
By tripling the radius, you would increase the volume nine times.
A cylinder measures 3 cm tall with a radius of 2 cm. Explain whether tripling only the radius or height of the cylinder would triple the amount of volume.
Check It Out! Example 2B
V = 36 • 3 = 108 cm3
The original cylinder has a volume of 4 • 3 = 12 cm3.
Holt CA Course 1
10-2 Volume of Prisms and Cylinders
Check It Out! Example 2B Continued
Tripling the height would triple the volume.
V = 4 • 9 = 36 cm3
The original cylinder has a volume of 4 • 3 = 12 cm3.
Holt CA Course 1
10-2 Volume of Prisms and Cylinders
A drum company advertises a snare drum that is 4 inches high and 12 inches in diameter. Estimate the volume of the drum.
Additional Example 3: Music Application
d = 12, h = 4
r = = = 6
Volume of a cylinder
d 2V = (r2)h
12 2
= (3.14)(6)2 • 4
= (3.14)(36)(4)
= 452.16 ≈ 452
Use 3.14 for .
The volume of the drum is approximately 452 in3.
Holt CA Course 1
10-2 Volume of Prisms and Cylinders
A drum company advertises a bass drum that is 12 inches high and 28 inches in diameter. Estimate the volume of the drum.
Check It Out! Example 3
d = 28, h = 12
r = = = 14
Volume of a cylinder
d 2V = (r2)h
28 2
= (3.14)(14)2 • 12
= (3.14)(196)(12)
= 7385.28 ≈ 7,385
Use 3.14 for .
The volume of the drum is approximately 7,385 in3.
Holt CA Course 1
10-2 Volume of Prisms and Cylinders
Find the volume of the the barn.
Volume of barn
Volume of rectangular
prism
Volume of triangular
prism+=
= 30,000 + 10,000
V = (40)(50)(15) + (40)(10)(50)12
= 40,000 ft3
The volume of the barn is 40,000 ft3.
Additional Example 4: Finding the Volume of Composite Figures
Holt CA Course 1
10-2 Volume of Prisms and CylindersCheck It Out! Example 4
Find the volume of the play house.
3 ft
4 ft
8 ft
5 ft
V = (8)(3)(4) + (5)(8)(3)12
= 96 + 60
V = 156 ft3
Volume of house
Volume of rectangular
prism
Volume of triangular
prism+=
The volume of the play house is 156 ft3.
Holt CA Course 1
10-2 Volume of Prisms and CylindersLesson Quiz
Find the volume of each figure to the nearest tenth. Use 3.14 for .
306 in3942 in3 160.5 in3
No; the volume would be quadrupled because you have to use the square of the radius to find the volume.
10 in.
8.5 in.3 in.
12 in.12 in.
2 in.
15 in.10.7 in.
1. 3.2.
4. Explain whether doubling the radius of the cylinder above will double the volume.
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