Monday, May 19, 2008

Elearn Geometry Problem 71



See complete Problem 71
Cyclic Quadrilateral, Angles. Level: High School, SAT Prep, College geometry

Post your solutions or ideas in the comments.
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5 comments:

  1. AnonymousNovember 18, 2008 at 9:03 AM

    ABCD is a cyclic quadrilateral therefore angle beta and angle BCD are supplimentary. So beta + BCD = 180 degrees. Also, alpha + angle BCD = 180 degrees because they lie on a straight line. therefore alpha equals beta.

    Can anyone tell me if this is right?

    ReplyDelete
  2. Antonio GutierrezNovember 18, 2008 at 10:06 AM

    Yes, it is right. Q.E.D.

    ReplyDelete
  3. Eder Contreras OrdenesApril 7, 2012 at 11:00 PM

    Video-solution

    http://www.youtube.com/watch?v=D-DFhH8XYgM

    Note that the reciprocal is true.

    ReplyDelete
  4. AnonymousApril 23, 2014 at 8:39 PM

    β+∡BCD=180°
    β=180°-∡BCD
    α+∡BCD=180°
    α=180°-∡BCD
    α=β

    ReplyDelete
  5. UnknownAugust 24, 2016 at 7:11 PM

    β+∡BCD=180°
    β=180°-∡BCD
    α+∡BCD=180°
    α=180°-∡BCD
    α=β

    ReplyDelete

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