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Proofs will parallel lines

  1. Sep 25, 2006 #1
    I need to prove that <acb is equal to one of the other interior angles of triangle abc.

    help when pic uploads

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  2. jcsd
  3. Sep 26, 2006 #2


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    What do you know about the size of an exterior angle relative to the size of the other two angles in the interior?
    If CZ, the bisector of that angle, is parallel to AB, what does that tell you about angles BAC and ACZ?
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