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        riddles >> medium >> collinear points
        
(Message started by: tony123 on Nov 17^th, 2007, 1:43am)

Title: collinear points
Post by tony123 on Nov 17^th, 2007, 1:43am

A, B, C, D are collinear points in this order. Draw the regular triangles ABE and CDF on one side of the line. Let G denote the intersection of the circles ACE and BDF on the same side of the line ABCD. Prove that < AGD=120 °.