Lesson 3.2.notebook
October 02, 2012
Warm‐up
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Lesson 3.2.notebook
October 02, 2012
Page 131 Homework Answers
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Lesson 3.2.notebook
October 02, 2012
Lesson 3.2 ‐ Proving Lines Parallel
Postulate 3.2 ‐ Converse of the Corresponding Angles Postulate
If two lines and a transversal form corresponding angles that are congruent, then the two lines are parallel.
Theorem 3.5 ‐ Converse of the Alternate Interior
Angles Theorem
If two lines and a transversal form alternate interior angles that are congruent, then the two lines are parallel.
Theorem 3.6 ‐ Converse of the Same‐Side Interior
Angles Theorem
If two lines and a transversal form same‐
side interior angles that are supplementary, then the two lines are parallel.
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Lesson 3.2.notebook
October 02, 2012
Theorem 3.7 ‐ Converse of the Alternate Exterior Angles Theorem
If two lines and a transversal form alternate exterior angles that are congruent, then the two lines are parallel.
Theorem 3.8 ‐ Converse of the Same‐Side Exterior Angles Theorem
If two lines and a transversal form same‐
side exterior angles that are supplementary, then the two lines are parallel.
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Proof of Theorem 3.5
Given: <1 ≅ <2
Prove:
l ll m
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Lesson 3.2.notebook
Ex 1:
October 02, 2012
Use the diagram below. Jusfy your answers with a theorem or postulate.
a) Which lines, if any, must be parallel if <3 and <2 are supplementary?
b) Which lines, if any, must be parallel is <3 ≅ <4?
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Lesson 3.2.notebook
Ex 2:
October 02, 2012
Write a two‐column proof for Theorem 3.7.
Given: <1 ≅ <2
Prove: a ll b
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Ex 3:
October 02, 2012
Find the value of x for which l ll m.
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Lesson 3.2.notebook
October 02, 2012
Homework: Page 138 #2‐22 x2, 24, 25, 27‐31, 39‐40
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