Jumat, 17 September 2010

14th Balkan Mathematical Olympiad Problems 1997

00.11 Cool Math Games No comments

14th Balkan Mathematical Olympiad Problems 1997A1.  ABCD is a convex quadrilateral. X is a point inside it. XA2 + XB2 + XC2 + XD2 is twice the area of the quadrilateral. Show that it is a square and that X is its center.