MathDB

3

Part of 2003 JBMO Shortlist

Problems(1)

G,B,C,A' concyclic iff GA ⊥ GC (AC=CA')

Source: JBMO Shortlist 2003

10/12/2017
Let GG be the centroid of triangle ABCABC, and A′A' the symmetric of AA wrt CC. Show that G,B,C,A′G, B, C, A' are concyclic if and only if GA⊥GCGA \perp GC.
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