1. Splash Screen

2. Five-Minute Check (over Lesson 12–2) Then/Now
Key Concept: Volume of a Cylinder
Example 1: Volume of a Cylinder
Example 2: Height of a Cylinder
Example 3: Real-World Example: Volume of a Composite Figure
Lesson Menu

3. Find the volume of the figure.
A. 80 cm2
B. 85 cm3
C. 400 cm2
D. 400 cm3
5-Minute Check 1

4. Find the volume of the figure.
A. 864 in3
B. 432 in3
C. 216 in3
D in3
5-Minute Check 2

5. The volume of a triangular prism is 375 cubic centimeters
The volume of a triangular prism is 375 cubic centimeters. The area of the base is 50 square centimeters. What is the height of the prism?
A cm2
B cm
C. 7.5 cm2
D. 7.5 cm
5-Minute Check 3

6. A cubic inch of water weighs 0. 036 pound
A cubic inch of water weighs pound. A 10-gallon fish tank measures 20 inches by 10 inches by 12 inches. How much will the water in the fish tank weigh if it is filled to capacity?
A pounds
B pounds
C pounds
D pounds
5-Minute Check 4

7. What is the volume of the house?
A. 2,662 m3
B. 10,560 m3
C. 12,870 m3
D. 15,180 m3
5-Minute Check 5

8. You have already found the areas of circles. (Lesson 11–8)
Find the volumes of circular cylinders.
Find the volumes of composite figures involving circular cylinders.
Then/Now

9. Concept

10. A. Find the volume of the cylinder. Round to the nearest tenth.
Volume of a Cylinder
A. Find the volume of the cylinder. Round to the nearest tenth.
V = Bh Volume of a cylinder
V = πr2h Replace B with πr2.
V ≈ 3.14 ● 72 ● 14 Replace π with 3.14, r with 7, and h with 14.
V ≈ Simplify.
Answer: The volume is about cubic feet.
Example 1 A

11. Since the diameter is 10 meters, the radius is 5 meters.
Volume of a Cylinder
B. Find the volume of the cylinder. Round to the nearest tenth. diameter of base 10 m, height 2 m
Since the diameter is 10 meters, the radius is 5 meters.
V = πr2h Formula for volume of a cylinder
V ≈ 3.14 ● 52 ● 2 Replace π with 3.14, r with 5, and h with 2.
V ≈ 157 Simplify.
Answer: The volume is about 157 cubic meters.
Example 1 B

12. A. Find the volume of the cylinder. Round to the nearest tenth.
A in3
B. 336 in3
C in3
D in3
Example 1 CYP A

13. B. Find the volume of the cylinder with a base diameter of 8 cm and a height of 6 cm. Round to the nearest tenth.
A cm3
B cm3
C cm3
D cm3
Example 1 CYP B

14. V = Bh Volume of a cylinder V = πr2h Replace B with πr2.
Height of a Cylinder
The volume of the cylinder is 99 cubic inches. Find the height of the cylinder. Round to the nearest tenth.
V = Bh Volume of a cylinder
V = πr2h Replace B with πr2.
99 ≈ 3.14 ● 32 ● h Replace V with 99, π with 3.14, and r with 3.
Example 2

15. Answer: The height is about 3.5 inches.
Height of a Cylinder
99 ≈ h Simplify.
3.5 ≈ h Divide each side by
Answer: The height is about 3.5 inches.
Example 2

16. The volume of a cylinder is 678 cubic inches
The volume of a cylinder is 678 cubic inches. Find the height of the cylinder. Round to the nearest tenth.
A. 6.0 in.
B. 6.4 in.
C. 7.2 in.
D. 7.5 in.
Example 2

17. Step 1 Find the volume of the prism.
Volume of a Composite Figure
CAKES A baker designed a wedding cake in the shape shown below. Find the volume of the cake.
Step 1 Find the volume of the prism.
V = Bh Volume of a prism
= 20 ● 20 ● 4 The length and width are The height is 4.
= 1600 in3 Multiply.
Example 3

18. Step 2 Find the volume of the cylinder.
Volume of a Composite Figure
Step 2 Find the volume of the cylinder.
V = πr2h Volume of a cylinder
≈ 3.14(5)2(4) Replace r with 5 and h with 4.
≈ 314 in3 Multiply.
Step 3 Find the volume of the composite figure in in3 = 1914 in3
Answer: The volume of the cake is 1914 in3.
Example 3

19. CAKES A wedding cake has two layers that are cylinders
CAKES A wedding cake has two layers that are cylinders. Each layer has a height of 3 inches. The bottom layer has a radius of 12 inches. The upper layer has a radius of 8 inches. What is the volume of the cake?
A in3
B in3
C in3
D in3
Example 3

20. End of the Lesson