Section 12-3: Surface Areas of Pyramids and Cones
By the end of this lesson, you should be able to answer:
• How do you find lateral areas and surface areas of pyramids?
• How do you find lateral areas and surface areas of cones?
Vocabulary:
Regular Pyramid
Slant Height
Right Cone
Oblique Cone
Parts of a Pyramid
Lateral Area of a Regular Pyramid:
Surface Area of a Regular Pyramid:
Example 1: Find the lateral area and the surface area of the square pyramid. The base
has a side length of 2.5 cm and a slant height of 5 cm.
Example 2: Find the surface area of the square pyramid to the nearest hundredth.
Parts of a Cone
Lateral Area of a Cone:
Surface Area of a Cone:
Example 3: An ice cream cone has an altitude of 8 inches and a diameter of 2.5 inches.
Find the lateral area of the cone to the nearest hundredth.
Example 4: Find the surface area of the cone. Round to the nearest hundredth.
Solid
Model
Lateral Area
Surface Area
Problem Set:
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