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Proving that Lines are Parallel - Lesson 5-2

Today, we covered a number of theorems regarding how to prove that lines are parallel. In order to prove these, we started by explaining what an exterior angle was:

Exterior Angle

You should be able to recognize that there are 6 exterior angles for every triangle. We then covered a number of theorems that can be proved based on the first (#30). The proof for Theorem 30 and the others, which follow directly from that, are in the sure that they make sense to you!!

Theorems 29 - 32

We did prove one of these in class...Theorem 31. The others are very similar.

AIP Proof


You should be able to see how you could prove AEP & CAP by a similar method.

At this point, we covered a number of other theorems:

Theorems 33 - 35


And wrapped up by doing an example (which is the proof for Theorem 35):

Example using CAP

Other Links
Class Notes
Lesson 5-1
Lesson 5-2
Lesson 5-3
Quiz Topics
Lesson 5-4
Lesson 5-5
Lesson 5-6
Lesson 5-7
Test Topics
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