MathDB
Line ZN is parallel to the bases of the trapezoid

Source: Tuymaada 2008, Junior League, Second Day, Problem 6.

July 20, 2008
geometrytrapezoidanalytic geometryratioperpendicular bisectorangle bisectorprojective geometry

Problem Statement

Let ABCD ABCD be an isosceles trapezoid with ADBC AD \parallel BC. Its diagonals AC AC and BD BD intersect at point M M. Points X X and Y Y on the segment AB AB are such that AX \equal{} AM, BY \equal{} BM. Let Z Z be the midpoint of XY XY and N N is the point of intersection of the segments XD XD and YC YC. Prove that the line ZN ZN is parallel to the bases of the trapezoid. Author: A. Akopyan, A. Myakishev