Some problems of seven circle 2

Let six points A,B,C,A', B', C' lie on a circle. B'C' meet AB,AC at Ac,Ab respectively. B'A' meets CA,CB at Cb,Ca reslpectively. A'B' meets BA,BC at Bc,Ba respectively. Six circles (AAbAc), (B'AbCb), (CCbCa), (A'CaCb), (BBcBa), (C'AcBa) meets (O) again at A1,B'1,C1,A'1,B1,C'1 respectively. a- Then A1A'1; B1B1'; C1C'1 are concurrent b-AA' meets A1A'1 at A2; BB' meets B1B'1 at B2; CC' meets C1C'1 at C2. Then A2,B2,C2 are collinear

 

Đào Thanh Oai

 
Resource Type
Activity
Tags
circle  collinear  concyclic  cyclic  dao  midpoints  oai  perpendicular  quadrilateral  tangential  thanh thebault theorem triangle Show More…
Target Group (Age)
19+
Language
English (United Kingdom)
 
 
GeoGebra version
4.4
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