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The common tangent to (I), (N) is parallel to Euler line

Source: Indian IMO Training Camp 2007-ST 1 P1

March 5, 2011
Eulergeometrytrigonometryperpendicular bisectorgeometry unsolved

Problem Statement

Show that in a non-equilateral triangle, the following statements are equivalent: (a)(a) The angles of the triangle are in arithmetic progression. (b)(b) The common tangent to the Nine-point circle and the Incircle is parallel to the Euler Line.