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Topic: Geometry August 09 Proof
Replies: 7   Last Post: Jun 11, 2010 1:15 PM

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Posts: 141
Registered: 12/3/04
Geometry August 09 Proof
Posted: Jun 10, 2010 12:24 PM
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While reviewing question 38 on the Geometry August 2009 exam, a student of mine mentioned a unique way to prove AB parallel to CD. His reasoning:

1. BF and DE are both perpendicular to AC and thus are parallel.

2. As angles 1 and 2 are given congruent, AB is parallel to CD.

We justified statement 1, and reasoned that 2 congruent angles containing a pair of parallel rays must also have its other rays parallel.

Has anyone else seen such reasoning? Can the justification be cleaned up a bit?

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