85 Angle of Elevation and Depression 2011 1 February 14, 2011 8.5 Angles of Elevation and Depression Objective: Use angles of elevation and depression to solve problems.
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8.5 Angles of Elevation and Depression
Objective:Use angles of elevation and depression to solve problems.
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Warm Up
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Horizontal
Line of sight
Object
Angle of depressionLin
e of sig
ht
Angle of elevation
Object
Vertical heights can be measured using either the angle of elevation or the angle of depression.
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horizontal line
horizontal line
angle of depression
angle of elevation
38o
38o
Suppose a person on the ground sees a hot-air balloon at a 38o angle above a
horizontal line.
This is the angle of elevation.
At the same time, the hot-air balloon sees the person on the ground at a 38o
angle below a horizontal line.
This is the angle of depression.
Why are the angles equal?
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Identify angles 1 - 4 as angles of elevation or angles of depression.
1
23
4
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A surveyor levels a theodolite (a surveying tool) with the bottom of the arch.
From there, she measures the angle of elevation to the top of the arch.
She then measures the distance from where she stands to a point directly under the arch.
What is the height of the arch?
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32o
1000
x
You sight a rock climber on a cliff at a 32o angle of elevation. The horizontal ground distance to the cliff is 1000 ft. Find the line-of-sight distance to the rock climber.
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To approach runway 17 of the Ponca City Municipal Airport in Oklahoma, the pilot must begin a 3o descent starting from an altitude of 2714 ft. The airport altitude is 1007 ft. How many miles from the runway is the airplane at the start of this approach?
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Homework: page 447
(1 - 14, 28, 35 - 37)