5.10 ­ Cosine Ratio (complete).notebook
March 04, 2013
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5.10 ­ Cosine Ratio (complete).notebook
March 04, 2013
Cosine Ratio
• Compares the length of the side adjacent to the angle
being considered to the length of the hypotenuse
.
• Therefore, cosine is equal to
Example 1
Fill in the blanks. For
The cosine ratio can be used to find missing side lengths
and angle measures in RIGHT TRIANGLES ONLY.
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5.10 ­ Cosine Ratio (complete).notebook
March 04, 2013
Example 2
Evaluate the following to 3 decimal places. (Either with a calculator, or a trig. table)
To find an angle measure given its cosine ratio, use the
key on
your calculator (inverse cosine). Be sure your calculator is in degree
mode.
Example 3
Determine the following angles.
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5.10 ­ Cosine Ratio (complete).notebook
March 04, 2013
Example 4
Solve the following triangles for the unknown value indicated.
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5.10 ­ Cosine Ratio (complete).notebook
March 04, 2013
Example 5
The length of the Leaning Tower of Pisa is about 55 m.
Today, the tower is about 4.5 m out of vertical alignment.
a. What is the measure of
b. What is the vertical height,
, to the nearest degree?
of the Tower?
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5.10 ­ Cosine Ratio (complete).notebook
March 04, 2013
Homework: Worksheet
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