This section will require you to think about and use parallel lines. Although some of the theorems and ideas may seem obvious, you must always be ready to provide justification for any statements made.

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This section will require you to think about and
use parallel lines. Although some of the
theorems and ideas may seem obvious, you must
always be ready to provide justification for any
statements made.
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POSTULATE
Corresponding Angles Postulate
THEOREMS
Alternate Interior Angles
Consecutive Interior Angles
Alternate Exterior Angles
Perpendicular Transversal
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Extra Example 1
Statements Reasons 1. 1. 2.
2. 3. 3. 4.
4. 5. 5. 6. 6.
Given
Linear Pair Post.
Substitution
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Extra Example 2
a. b. c. d.
70
Linear Pair Postulate
70
110
70
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Checkpoint
Extra Example 3
In the diagram above, how many angles have a
measure of 100?
eight
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Extra Example 4
Use properties of parallel lines to find the
value of x.
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Extra Example 5
Refer to Example 5. We now know that the diameter
of Earth is about 7973 mi. Recalculate the
distance between Syene and Alexandria using this
figure.
Using the equation from Example 5
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Checkpoint
x 65
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QUESTION
If a transversal is perpendicular to one of two
parallel lines, what is the measure of all the
angles formed?
ANSWER
90