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12.3b Surface Area of Pyramids and Cones. State Standards. Lesson Goals. Find the surface area of a cone. 8 , 9: Solve problems involving the surface area lateral area of geometric solids and COMMIT TO MEMORY THE NECESSARY FORMULAS. altitude. slant height. definitions. Cone - PowerPoint PPT Presentation
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12.3b Surface Area of Pyramids and Cones
State Standards8, 9: Solve problems involving
the surface area lateral area of geometric solids and COMMIT TO MEMORY THE NECESSARY FORMULAS.
Lesson Goals• Find the surface area of a
cone.
definitions• Cone
– Base: a circle– Lateral surface: a sector of a circle– Altitude: the perpendicular distance between the vertex
and the base.
slant heightaltitude
theorem
Surface Area of a Cone
represents the radius of the circle.r
You tryFind the surface area.
12 ft
5 ft
13 ft
2SA r r
25 5 13SA
25 65SA 22 282.6 ft90 ftSA
2 2 25 12 2 169
13
Example2SA r r
26.7 6.7 12.2SA
44.89 81.74SA
22 397.82 ft126.63 ftSA
2 2 26.7 10.2 2 44.89 104.04
2 148.93 12.2
Find the missing measurements of the right cone.
2SA r r
219.9 25 5
219.9 25 5
70 25 5
45 5
9 in
Find the missing measurements of the right cone.
Today’s Assignmentp. 738: 20 – 25, 27, 36, 44 – 46