r1719

Let P be a point, r a line through P. Let A’ be the second intersection between r and the circle {PBC} and define analogously B’, C’. Let Oa, Ob, Oc be the circumcenters of PBC, PCA, PAB. Let A* be the intersection between BC and OaA’ , and B*, C* its analogous. The points A*, B*, C* are collinear.


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