parallelism and concurrency
Source: ITAMO 2013 problem 5
May 11, 2013
geometrycircumcircleparallelogramrhombusperpendicular bisectorgeometry unsolved
Problem Statement
is an isosceles triangle with and the angle in is less than . Let be a point on such that . is the intersection between the perpendicular bisector of and the line parallel to passing through . is a point on the line such that ( is between and ).
Show that and are parallel and that the perpendicular from to , the perpendicular from to and are concurrent.