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From:
 "Darij Grinberg" <darij_grinberg@w...> Date: Fri Apr 23, 2004 7:00 am Subject: Re: X(155) !! | ||
In Hyacinthos message #9739, you wrote: >> Regarding X(155): I found this in the ETC database: >> >> "This point is also the center of the circle which >> cuts (extended) lines BC, CA, AB in pairs of points >> A' and A", B' and B", C' and C", respectively, such >> that angles A'AA", B'BB", C'CC" are all right >> angles. This is the Dou circle, described in >> >> Jordi Dou, Problem 1140, Crux Mathematicorum, 28 >> (2002) 461-462." This source is avaliable on the internet: Problem 55 "Solución parcial de Dan Sokolowsky Crux Mathematicorum (13(1987)232) (28 de octubre de 2002)". See also Hyacinthos messages #5811 and #5815, and Paul Yiu's "Geometric Constructions VIII", Solution of GC 18 on http://www.math.fau.edu/yiu/Geometry.html Sincerely, Darij Grinberg |
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