Geometry: An Interactive Journey to Mastery

Lesson 23: Three-Dimensional Geometry—Solids

x UHJXODUFRQHorUHJXODUF\OLQGHU: A cone or cylinder is said to be regular if its base is a regular

polygon and all of its lateral faces are congruent.

x VODQWKHLJKW: The slant height of a circular cone with cone point above the center of its base is the

distance of the cone point from any point on the perimeter of the base. The slant height of a regular

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x volume of a cylinder, right or oblique

V = area base × height.

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x volume of a cone

V =^13 area base × height.

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x volume and surface area of right circular cylinder

V = ʌU^2 h.

lateral area = 2ʌUK.

total surface area = 2ʌUK + 2ʌU^2.

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V =^13 ʌU^2 h.

lateral area = ʌUV.

total surface area = ʌUV + ʌU^2.

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h

Figure 23.3

Figure 23.4

r

h

Figure 23.5

r

slant height s

Figure 23.6