Given a circle O and three chords AB, AC, and AD. Circles O1, O2, and O3 are constructed with diameters AB, AC, and AD, respectively. Circles O1 and O2 meet at E, Circles O1 and O3 meet at F. Circles O2 and O3 meet at G. Prove that (1) C,G,D are collinear; (2) C,B,E are collinear; (3) B,F,D are collinear) (4) E,F,G are collinear, the line EFG is called the Salmon line.
George Salmon (1819 - 1904) was an Irish mathematician and professor of mathematics at Trinity College Dublin.
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Ten problems: 1411-1420
Diameters and Chords
HTML5 and Dynamic Geometry
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