Saturday, August 14, 2021

1745. An Equilateral Triangle

2 comments:

  1. Given a point P in the plane of ABC let Pa=P(ABcCb), and define Pb, Pc cyclically. Then

    1) If P=X(15), PaPbPc is equilateral centered at
    2 \Sqrt{3} X(6) + (a^2+b^2+c^2) X(9730);

    2) If P=X(16), PaPbPc is equilateral centered at
    2 \Sqrt{3} X(6) - (a^2+b^2+c^2) X(9730);

    3) If P lies on the Lemoine axis (line X(187)X(237)), then Pa, Pb, Pc are collinear and lie on line (SA^2 : SB^2 : SC^2) ( barycentrics );

    4) For all P, lines APa, BPb, CPc concur in P.

    Note that ABcCb, AcBCa, AbBaC are homothetic to ABC.

    Regards,
    Elias M. Hagos

    ReplyDelete
  2. https://www.facebook.com/photo?fbid=959389341574915&set=gm.2961116324131387

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