Section1.4_Part2_Surface_Area_of_Cones.notebook
October 02, 2012
Finding Missing unknowns given the surface area of a
Right Pyramid, Cone, Prism or cylinder.
(Major topic—study for LA)
Example 1:The surface area of a right cone is 125 in. 2 and
its radius is 4.7 in. What is the slant height of
the right cone?
Step 1: Sketch a diagram.
A = 125 in 2
s
r = 4.7 in
Step 2: Use the formula for Surface Area to find the
slant height, s.
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Section1.4_Part2_Surface_Area_of_Cones.notebook
October 02, 2012
Example 2: The lateral area of a cone is 450 m². The
diameter of the cone is 15 m. Determine the
height of the cone to the nearest tenth of a
centimeter.
Step 1: Sketch a diagram.
15 m
Recall: AL = πrs and r = ½d
h
s
Step 2: Use the formula for lateral area to find the slant
height, s.
Step 3: Use Pythagorean Theorem to find the height of
the cone.
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Section1.4_Part2_Surface_Area_of_Cones.notebook
October 02, 2012
Example 3:A cylinder has a surface area of 412 cm2. The
height is 3 times greater than the radius. Approximate the
height of the cylinder.
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