Section 12-5
Volumes of Pyramids and Cones
Essential Questions
• How do you find volumes of pyramids?
• How do you find volumes of cones?
Volume of a Pyramid
Volume of a Pyramid
V = 1
3 Bh
Volume of a Pyramid
B = area of the base
V = 1
3 Bh
Volume of a Pyramid
B = area of the base
h = height of the pyramid
V = 1
3 Bh
Example 1
Find the volume of the pyramid.
Example 1
Find the volume of the pyramid.
V = 1
3 Bh
Example 1
Find the volume of the pyramid.
V = 1
3 Bh
B = area of the
square base
Example 1
Find the volume of the pyramid.
V = 1
3 Bh
B = area of the
square base
V = 1
3 (3)2
(7)
Example 1
Find the volume of the pyramid.
V = 1
3 Bh
B = area of the
square base
V = 1
3 (3)2
(7)
V = 21 in3
Volume of a Cone
Volume of a Cone
V = 1
3 Bh or V = 1
3 πr2
h
Volume of a Cone
V = 1
3 Bh or V = 1
3 πr2
h
B = area of the base: B = πr2
Volume of a Cone
h = height of the cone
V = 1
3 Bh or V = 1
3 πr2
h
B = area of the base: B = πr2
Example 2
Find the volume of the cone to the nearest hundredth.
Example 2
Find the volume of the cone to the nearest hundredth.
V = 1
3 πr2
h
Example 2
Find the volume of the cone to the nearest hundredth.
V = 1
3 πr2
h
V = 1
3 π(5)2
(12)
Example 2
Find the volume of the cone to the nearest hundredth.
V = 1
3 πr2
h
V = 1
3 π(5)2
(12)
V ≈ 314.16 cm3
Example 3
Find the volume of the cone to the nearest hundredth.
Example 3
Find the volume of the cone to the nearest hundredth.
V = 1
3 πr2
h
Example 3
Find the volume of the cone to the nearest hundredth.
V = 1
3 πr2
h
V = 1
3 π(3.5)2
(13)
Example 3
Find the volume of the cone to the nearest hundredth.
V = 1
3 πr2
h
V = 1
3 π(3.5)2
(13)
V ≈166.77 ft3
Example 4
At the top of a stone tower is a pyramidion in the shape of a
square pyramid. The pyramid has a height of 52.5 centimeters
and the base edges are 36 centimeters. What is the volume of
the pyramidion rounded to the nearest hundredth?
Example 4
At the top of a stone tower is a pyramidion in the shape of a
square pyramid. The pyramid has a height of 52.5 centimeters
and the base edges are 36 centimeters. What is the volume of
the pyramidion rounded to the nearest hundredth?
V = 1
3 Bh
Example 4
At the top of a stone tower is a pyramidion in the shape of a
square pyramid. The pyramid has a height of 52.5 centimeters
and the base edges are 36 centimeters. What is the volume of
the pyramidion rounded to the nearest hundredth?
V = 1
3 Bh
V = 1
3 (36)2
(52.5)
Example 4
At the top of a stone tower is a pyramidion in the shape of a
square pyramid. The pyramid has a height of 52.5 centimeters
and the base edges are 36 centimeters. What is the volume of
the pyramidion rounded to the nearest hundredth?
V = 1
3 Bh
V = 1
3 (36)2
(52.5)
V = 22680 cm3
Problem Set
Problem Set
p. 860 #1-12, 17, 18 all; skip #2, 6
“From a small seed a mighty trunk may grow.” - Aeschylus

Geometry Section 12-5

  • 1.
    Section 12-5 Volumes ofPyramids and Cones
  • 2.
    Essential Questions • Howdo you find volumes of pyramids? • How do you find volumes of cones?
  • 3.
    Volume of aPyramid
  • 4.
    Volume of aPyramid V = 1 3 Bh
  • 5.
    Volume of aPyramid B = area of the base V = 1 3 Bh
  • 6.
    Volume of aPyramid B = area of the base h = height of the pyramid V = 1 3 Bh
  • 7.
    Example 1 Find thevolume of the pyramid.
  • 8.
    Example 1 Find thevolume of the pyramid. V = 1 3 Bh
  • 9.
    Example 1 Find thevolume of the pyramid. V = 1 3 Bh B = area of the square base
  • 10.
    Example 1 Find thevolume of the pyramid. V = 1 3 Bh B = area of the square base V = 1 3 (3)2 (7)
  • 11.
    Example 1 Find thevolume of the pyramid. V = 1 3 Bh B = area of the square base V = 1 3 (3)2 (7) V = 21 in3
  • 12.
  • 13.
    Volume of aCone V = 1 3 Bh or V = 1 3 πr2 h
  • 14.
    Volume of aCone V = 1 3 Bh or V = 1 3 πr2 h B = area of the base: B = πr2
  • 15.
    Volume of aCone h = height of the cone V = 1 3 Bh or V = 1 3 πr2 h B = area of the base: B = πr2
  • 16.
    Example 2 Find thevolume of the cone to the nearest hundredth.
  • 17.
    Example 2 Find thevolume of the cone to the nearest hundredth. V = 1 3 πr2 h
  • 18.
    Example 2 Find thevolume of the cone to the nearest hundredth. V = 1 3 πr2 h V = 1 3 π(5)2 (12)
  • 19.
    Example 2 Find thevolume of the cone to the nearest hundredth. V = 1 3 πr2 h V = 1 3 π(5)2 (12) V ≈ 314.16 cm3
  • 20.
    Example 3 Find thevolume of the cone to the nearest hundredth.
  • 21.
    Example 3 Find thevolume of the cone to the nearest hundredth. V = 1 3 πr2 h
  • 22.
    Example 3 Find thevolume of the cone to the nearest hundredth. V = 1 3 πr2 h V = 1 3 π(3.5)2 (13)
  • 23.
    Example 3 Find thevolume of the cone to the nearest hundredth. V = 1 3 πr2 h V = 1 3 π(3.5)2 (13) V ≈166.77 ft3
  • 24.
    Example 4 At thetop of a stone tower is a pyramidion in the shape of a square pyramid. The pyramid has a height of 52.5 centimeters and the base edges are 36 centimeters. What is the volume of the pyramidion rounded to the nearest hundredth?
  • 25.
    Example 4 At thetop of a stone tower is a pyramidion in the shape of a square pyramid. The pyramid has a height of 52.5 centimeters and the base edges are 36 centimeters. What is the volume of the pyramidion rounded to the nearest hundredth? V = 1 3 Bh
  • 26.
    Example 4 At thetop of a stone tower is a pyramidion in the shape of a square pyramid. The pyramid has a height of 52.5 centimeters and the base edges are 36 centimeters. What is the volume of the pyramidion rounded to the nearest hundredth? V = 1 3 Bh V = 1 3 (36)2 (52.5)
  • 27.
    Example 4 At thetop of a stone tower is a pyramidion in the shape of a square pyramid. The pyramid has a height of 52.5 centimeters and the base edges are 36 centimeters. What is the volume of the pyramidion rounded to the nearest hundredth? V = 1 3 Bh V = 1 3 (36)2 (52.5) V = 22680 cm3
  • 28.
  • 29.
    Problem Set p. 860#1-12, 17, 18 all; skip #2, 6 “From a small seed a mighty trunk may grow.” - Aeschylus