Splash Screen

1
Splash Screen
2
Lesson Menu
Five-Minute Check (over Lesson 125) Then/Now Key
Concept Lateral and Surface Area of
Cylinders Example 1 Surface Area of a
Cylinder Example 2 Real-World Example Compare
Surface Areas of Cylinders
3
5-Minute Check 1
Find the lateral area of the figure.
A. 197.6 cm2 B. 204.7 cm2 C. 247.6 cm2 D. 274.4
cm2

1. A
2. B
3. C
4. D

4
5-Minute Check 2
Find the surface area of the figure.
A. 96 in2 B. 98 in2 C. 106 in2 D. 108 in2

1. A
2. B
3. C
4. D

5
5-Minute Check 3
Find the lateral area of a cube with a length of
0.8 meter.
A. 2.4 m2 B. 2.6 m2 C. 3.6 m2 D. 3.8 m2

1. A
2. B
3. C
4. D

6
5-Minute Check 4
Amy needs to wrap a box that is 18 inches long,
11 inches wide, and 3 inches high. What is the
minimum amount of wrapping paper that she needs?
A. 512 in2 B. 520 in2 C. 570 in2 D. 594 in2

1. A
2. B
3. C
4. D

7
5-Minute Check 5
How much wood is needed to make a rectangular toy
box that measures 40 inches long, 30 inches wide,
and 24 inches high?
A. 3,360 in2 B. 5,760 in2 C. 7,630 in2 D. 28,800
in2

1. A
2. B
3. C
4. D

8
Then/Now
You have already found the lateral areas and
surface areas of prisms. (Lesson 125)

• Find lateral and surface areas of cylinders.

• Compare surface areas of cylinders.

9
Concept
10
Example 1 A
Surface Area of a Cylinder
A. Find the lateral area and surface area of
the cylinder. Round to the nearest tenth.
Lateral Area L 2prh 2p(5)(8) 80p exact
answer 251.3 in2 approximate answer
The lateral area is about 251.3 square inches.
11
Example 1 A
Surface Area of a Cylinder
Surface Area S L 2pr2 80p 2p(5)2
130p exact answer 408.4 in2 approximate
answer
The surface area is about 408.4 square inches.
Answer L 251.3 in2, S 408.4 in2
12
Example 1B
Surface Area of a Cylinder
B. Find the lateral area and surface area of the
cylinder. diameter of 18 feet and height of 9.5
feet
Lateral Area L 2prh 2 p 9 9.5 171p
537.2 ft2
The lateral area is about 537.2 square feet.
13
Example 1B
Surface Area of a Cylinder
Surface Area S L 2pr2 171p 2p(9)2
171p 162p 1046.2 ft2
The surface area is about 1046.2 square feet.
Answer L 537.2 ft2, S 1046.2 ft2
14
Example 1A CYP
A. Find the lateral area and the surface area of
the cylinder. Round to the nearest tenth.
A. lateral area, 1082.0 in2 surface area,
1504.4 in2 B. lateral area, 1082.0 in2 surface
area, 3852.9 in2 C. lateral area, 2163.9 in2
surface area, 2586.4 in2 D. lateral area, 4436.1
in2 surface area, 4858.6 in2

1. A
2. B
3. C
4. D

15
Example 1B CYP
B. Find the lateral area and the surface area of
the cylinder. Round to the nearest tenth.
diameter of 6 feet and height of 5 feet
A. lateral area, 47.1ft2 surface area, 56.5
ft2 B. lateral area, 94.2 ft2 surface area,
150.8 ft2 C. lateral area, 141.4 ft2 surface
area, 197.9 ft2 D. lateral area, 188.5 ft2
surface area, 301.6 ft2

1. A
2. B
3. C
4. D

16
Example 2
Compare Surface Areas of Cylinders
MANUFACTURING A company manufactures dowel rods.
Rod A has a diameter of 3 inches and a height of
12 inches. Rod B has a diameter of 1 inch and a
height of 36 inches. Which rod has the larger
surface area?
Find the surface area of both rods.
The diameter of Rod A is 3 inches, so radius is
1.5 inches. Its height is 12 inches. The
diameter of Rod B is 1 inch, so radius is 0.5
inch. Its height is 36 inches.
17
Example 2
Compare Surface Areas of Cylinders
Rod A S L 2pr 2 2prh 2pr 2
2p(1.5)(12) p(1.5)2 36p 2.25p
120.2 in2
Rod B S L 2pr 2 2prh 2pr 2
2p(0.5)(36) p(0.5)2 36p 0.25p 113.9
in2
Answer Rod A has the larger surface area.
18
Example 2
A cylindrical Brand A oatmeal container has a
radius of 5 inches and a height of 12 inches.
Brand B uses a cylinder with a radius of 4 inches
and a height of 14 inches. Which statement is
true?
A. Brand As container has the larger surface
area. B. Brand Bs container has the larger
surface area. C. The containers have the same
surface area. D. It is not possible to determine
the surface areas of the containers.

1. A
2. B
3. C
4. D

19
End of the Lesson