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Trisecting an angle

  1. Feb 15, 2007 #1
    i have read that it has been proven that an angle cannot be trisected using just a compass and a straight-edge (unless it is some specific angle, e.g., 90 degrees or 180 degrees). can anyone tell me where i can find the proof? can anyone suggest any website?
  2. jcsd
  3. Feb 15, 2007 #2


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    Buy an introductory book in algebra&group theory.
  4. Feb 15, 2007 #3


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    Last edited by a moderator: May 2, 2017
  5. Feb 15, 2007 #4


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    If you are allowed to mark the straight edge with a pencil, then you can certainly trisect any acute angle. Of course, with marking not permitted you cannot.
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