Name ———————————————————————
LESSON
12.3
Date ————————————
Practice A
For use with pages 842–849
1. Label the height, slant height, and base of the regular pyramid shown.
A
2. What kind of figure is the base?
3. What kind of figure is each lateral face?
B
F
4. How many lateral faces does the solid have?
5. Name three lateral edges.
C
E
D
Find the area of each lateral face of the regular pyramid.
6.
7.
8.
10 m
14 ft
24 cm
12 ft
9m
20 cm
Sketch a net of the regular pyramid. Find its surface area and lateral area.
Round your answers to two decimal places.
9.
10.
11.
FT
6 yd
7m
2m
4 yd
!FT
1.7 m
12.
13.
14.
16 yd
13 in.
15 cm
10 cm
24 yd
12 in.
LESSON 12.3
6.9 cm
Find the lateral area of the right cone. Round your answer to two
decimal places.
15.
16.
15 in.
7 in.
408
Geometry
Chapter 12 Resource Book
6m
17.
18 cm
8m
18 cm
Copyright © Holt McDougal. All rights reserved.
FT
Name ———————————————————————
LESSON
12.3
Practice A
For use with pages 842–849
continued
Date ————————————
LESSON
0.0
Find the surface area of the right cone. Round your answer to two
decimal places.
18.
19.
20.
32 mm
28 m
11 yd
25 mm
9m
5 yd
21.
22. 7 m
20 in.
23. 4 cm
24 m
13 cm
17 in.
Sketch the described solid and find its surface area. Round your
answer to two decimal places.
24. A regular pyramid has a square base with
and a slant height of 20 feet.
26. Find the lateral area of a right cone that has a radius of 27 centimeters and a height
of 36 centimeters. Round your answer to two decimal places.
27. Find the surface area of a right cone that has a diameter of 80 inches and a slant
height of 58 inches. Round your answer to two decimal places.
28. Gazebo The roof of a gazebo is shaped like a regular
square pyramid with base edge length 10 feet as shown.
Its lateral area is 120 square feet. Find the slant height.
LESSON 12.3
Copyright © Holt McDougal. All rights reserved.
a base edge length of 4 meters and a slant
height of 7 meters.
25. A right cone has a radius of 9 feet
10 ft
Geometry
Chapter 12 Resource Book
409
Lesson 12.2, continued
15. Check sketches; 154 yd2; 56 yd2.
12. 6940.8 cm2; 5177.97 cm2 13. 3583.49 in.2
16. Check sketches; 3600 in.2; 2800 in.2.
14. 3160.46 mm2 or 31.6 cm2 15. 402.42 m2
17. Check sketches; 167.66 m2; 138 m2.
16. 4.42 ft 17. 13.8 m 18. 5.75 yd
2
18. Check sketches; 275.14 ft ; 192 ft .
19. 1130.04 ft2 20. 5288.16 m2 21. 5 cm
19. 100.53 cm2; 75.40 cm2
22. 3 yd 23. 96 ft2
20. 904.78 ft2; 395.84 ft2
24. 301.59 m2 25. 82 cm2
21. 6880.09 m2; 5466.37 m2
26. 1163.96 yd2
22. 835.66 yd2; 527.79 yd2
Review for Mastery
23. 30,259.82 in.2; 25,333.80 in.2
2
24. 7.85 mm ; 6.28 mm
ANSWERS
2
1. 184 in.2; 144 in.2
2
2. 768π < 2412.74 cm2; 1507.96 cm2 3. 21 ft
2
25. 3 ft 26. 9 cm 27. 14 cm 28. 276 m
Problem Solving Workshop:
Using Alternative Methods
29. 33.8 cm2 30. 5 ft 31. 6 mm
1. 972 in.2 2. 860.55 m2
Practice Level B
1. Check sketches; 162 cm2
Challenge Practice
2. Check sketches; 4656 in.2
3. Check sketches; 345.58 ft
1. 1020 in.2 2. 320π < 1005 cm2 3. 6000 ft2
}}
2
}
4. d 5 Ï l2 1 w 2 1 h2 5. Ï 70 < 8.4 in.
}
4. Check sketches; 248 m2; 168 m2.
6. Check sketches; 228.06 cm2; 150 cm2.
6. 5Ï 3 < 28.7 cm 7. The diagonal length
doubles. 8. Length: 6 yd; width: 2 yd;
height: 4 yd 9. Height: 9 ft; radius: 2 ft
7. 628.32 cm2; 471.24 cm2
10. Height: 21 cm; radius: 13 cm
5. Check sketches; 309.21 ft2; 269.21 ft2.
8. 29.72 ft2; 22.12 ft2
Lesson 12.3
9. 2261.95 in.2; 1357.17 in.2
Practice Level A
10. 8 m 11. 10.23 ft 12. 11.89 cm
1.
13. S 5 2xy 1 2xz 1 2yz 14. 216 in.2
slant
height
height
Copyright © Holt McDougal. All rights reserved.
15. 184 in.2 16. B
1
17. The new surface area is } of the original
4
base
surface area.
18. 3 ft 19. 207.35 in.2 20. 2.5 ft
21. 70.69 ft2 22. 117.81 ft2
2. regular pentagon 3. triangle 4. 5
} } }
5. Sample answer: AC, AB, AE 6. 45 m2
7. 84 ft2 8. 260 cm2
Practice Level C
9. Check sketches; 64 yd2; 48 yd2.
1. Check sketches; 570.89 ft
2
2. Check sketches; 102.22 m
10. Check sketches; 52.2 m2; 42 m2.
2
3. Check sketches; 671.17 cm
11. Check sketches; 135.7 ft2; 108 ft2.
2
12. Check sketches; 547.5 cm2; 375 cm2.
2
2
4. Check sketches; 150.01 cm ; 89.87 cm .
2
13. Check sketches; 1536 yd2; 960 yd2.
2
5. Check sketches; 140.12 m ; 113.66 m .
2
14. Check sketches; 296.4 in.2; 234 in.2.
2
6. Check sketches; 29.76 mi ; 10.54 mi .
2
15. 329.87 in.2 16. 188.5 m2
2
7. Check sketches; 1984.5 in. ; 1488.38 in. .
2
2
17. 508.94 cm2 18. 251.33 yd2
2
8. Check sketches; 53.83 ft or 5.98 yd ; 42 ft
or 4.67 yd2.
9. Check sketches; 508.88 ft2; 334.08 ft2.
10. 1.52 m2; 1.13 m2 11. 1198.69 ft2; 391.65 ft2
19. 1046.15 m2 20. 2060.88 mm2
21. 761.05 in.2 22. 703.72 m2
23. 221.19 cm2
Geometry
Chapter 12 Resource Book
A59
Lesson 12.3, continued
24. 72 m2
25. 819.96 ft2
18. 14,003.96 in.2 19. 711.37 m2
20. 458.4 m2
20 ft
10 m
20.34 yd
4m
9 ft
26. 3817.04 cm2 27. 12,315.04 in.2 28. 6 ft
Practice Level B
Review for Mastery
4. Check sketches; 189 m2; 140 m2.
1. 37.5 m2 2. 337.5 m2; 187.5 m2
5. Check sketches; 588.44 ft2; 378.00 ft2.
3. Lateral area 5 260π < 816.8 yd2
6. Check sketches; 287.68 cm2; 214.5 cm2.
4. S 5 360π < 1131.0 yd2
7. 157.08 m2
8. 188.5 ft2 9. 304.52 cm2 10. 578.05 m2
11. 440.67 ft
2
12. 1160.06 cm
2
Problem Solving Workshop:
Mixed Problem Solving
13. C
1. a. rectangle b. 24 in., 32 in.2
c. right triangles d. 16 in.2 2. The candle shaped
15. 252.85 in.2
14. 756 in.
12 in.
10 in.
12 in.
18 in.
12 in.
16. 117.69 ft2
22. 178.67 cm2 23. 23,071.86 in.2
24. 1181.36 ft2
1. 12 m2 2. 48 ft2 3. 232.05 cm2
2
16.90 yd
8m
12 in.
17. 282.74 m2
3 ft
12 m
9 ft
like a cone needs to have more plastic wrapped
around it because it has a larger surface area than
the candle shaped like a regular square pyramid.
3. a. 600 m2 b. Double each side of the base.
c. Double each side of the base: 1440 m2, double
the height: 1080 m2; Doubling each side of the
base creates a greater surface area than doubling
the height. 4. a. 360 ft2 b. 2 c. about 128.1 ft2
d. 2 5. Answers will vary. 6. 16.3 ft2
Challenge Practice
9m
1. Slant height: 10 in.; radius: 5 in.
2. Slant height: 13 cm; side length of base: 7 cm
18. 480 m2 19. 119.38 in.2 20. 124.71 cm2
21. 611.76 ft 22. 231,243.64 ft2
1
7. R 5 5 yd 8. S 5 B1 1 B2 1 } (P1 1 P2)l,
2
Practice Level C
1. 25.46 cm2 2. 251.56 ft2 3. 134.23 m2
2
2
4. Check sketches; 124.99 m ; 88.99 m .
5. Check sketches; 171.83 cm2; 126 cm2.
6. Check sketches; 134.61 ft2; 110.25 ft2.
7. Check sketches; 671.06 yd2; 362.04 yd2.
8. Check sketches; 508.71 m2; 358.11 m2.
9. Check sketches; 125.12 in.2; 93.83 in.2.
10. 353.69 m2 11. 157.63 yd2 12. 332.35 mm2
13. 298.45 cm2 14. 170.99 m2 15. 352.58 cm2
16. 1487.93 ft2 17. 126.67 yd2
Geometry
Chapter 12 Resource Book
}}
4. S 5 π(r 1 R)Ï (R 2 r)2 1 h2 1 πr2 1 πR2
5. 282π < 885.9 ft2 6. about 634.3 m2
23. 924,974.57 ft2
A60
3. S 5 π(r 1 R)l 1 πr 2 1 πR2
where B1 is the area of the base, B2 is the area of
the top, P1 is the perimeter of the base, P2 is the
perimeter of the top, and l is the slant height.
111 }
9. 645 m2 10. 147 1 }Ï 3 < 243.1 ft2
2
11. 36 mm
Lesson 12.4
Practice Level A
1. 40 cubic units 2. 240 cubic units
3. 84 cubic units 4. 8 ft3 5. 105 m3 6. 40 cm3
Copyright © Holt McDougal. All rights reserved.
ANSWERS
7m
21. 809.01 yd2