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Conference rusure::math

Title:Mathematics at DEC
Moderator:RUSURE::EDP
Created:Mon Feb 03 1986
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:2083
Total number of notes:14613

808.0. "<><><> Brocard points ... <><><>" by KEEPER::KOSTAS (He is great who confers the most benefits.) Wed Dec 23 1987 22:38

    Hello,
    
         How can a three sided figure betermine two points?
    
    Enjoy,
    
    Kostas
    
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808.1related info and problems ...KEEPER::KOSTASHe is great who confers the most benefits.Sun Dec 27 1987 21:2829
    Some related info:
    
         Because of the three-way symmetry of triangles, the idea that
    a three sided figure determines two points, seems at first sight
    as puzzling as that lines which cut off thirds from the sides should
    cut out one-seventh of the area.
    
    The points were first brought to the attention of mathematicians
    by H. Brocard (1845-1922), and they have received a great deal of
    study and found to possess many interesting properties.
    
    The "2-ness" comes from the fact that a line to a vertex makes an
    angle clockwise to one side and counter-clockwise to the other.
    A Brocard point connected with the three vertices makes the alternate
    set of angles, all clockwise or all counter-clockwise, equal.
    
    Some questions:
    
       1.  For a 3-4-5 triangle find the Brocard points.

       2.  For a triangle whose sides are 13, 14, 15 and one altitute
           is 12, the area is 84, the sum of the squares of the sides
           is 590, find the Brocard points.
    
    /Enjoy,
    
    Kostas
    
    
808.2CLT::GILBERTBuilderMon Jan 04 1988 12:549
    Three (non-colinear) points determine a circle, and this determines
    two points: the centers of the inscribed and circumscribed circles.

    In fact, you can choose any two singular points determined by the
    three given points:

	o  Center of the inscribed circle
	o  Center of the circumscribed circle
	o  Mean of the three points (average the x-y coordinates).