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Lesson 31Surface Area and Volume of PyramidsHomework WS 7.3
Surface Area and Volume - Pyramids
SA = ½lp + BSurface Area Formula:_________________________
Surface Area and Volume - Pyramids
__________________
____________________________________
side
slant heightl
height
First thing to look for: _____________________________________the shape of the base
__________________________________square pyramid
(or altitude)
Surface Area – Pyramid
1. Find the surface area of each regular pyramid with side length s, and slant height l. The number of sides of the base is given by n.
s = 6 l = 7 n = 4SA = ½lp + BSA = ½lp + lw
Square-lw
SA = ½(7)(24) + 36 SA = 84 + 36SA = 120
Surface Area and Volume - Pyramids
2. Find the surface area with side length s and slant height l, with the number of sides of the base given by n.
SA = ½lp + B
First thing to look for?: _____________________________________
s =8 L = 9 n = 3shape of the base
__________________triangle
SA = ½lp + ½bhSA = ½(9)(24) + ½(8)(43)SA = 135.7
Surface Area and Volume - Pyramids
The __________________of a solid is the total number of cubes that will exactly fill the interior.
volume
V = ⅓BhVolume Formula:_________________________
Where B is:________________________area of the base
3. V = ⅓Bh
4m
3m
7.6
Volume – PyramidFirst thing to look for: _____________________________________shape of the base
V = ⅓(12)(7.6)
V = 30.4 m³
Surface Area and Volume - Pyramids
4. A pentagonal pyramid with a base area of 24 square units and a volume of 104 cubic units. What is the height?
V = ⅓Bh104 = ⅓(24)h
104 = 8h13 = h
Surface Area and Volume - Pyramid
5. Find the volume of a square pyramid with the given dimensions.Base edge of 4, and a height equal to the diagonal of the base
4
442
V = ⅓Bh
V = ⅓(16)42
V = 30.2
Surface Area and Volume - Pyramid
6. A pyramid has a right triangle as its base, with leg lengths of 5 and 12. If the pyramids volume is 100, find its altitude.
V = ⅓Bh
5
12
100= ⅓(½(5)12)h100= ⅓(30)h100= 10h
10 = h
Surface Area and Volume - Pyramids
7. Find the surface area of a pyramid with the given dimensions.
n = 3, s = 14, l = 14First thing to look for: _____________________________________shape of the base
__________________triangleSA = ½lp + B
14
1414
7
73SA = ½(14)42 + ½(14)73SA = 294 + 84.9SA = 378.9