MathDB
2001 KJMO P8 distance between a line and a point

Source: 2001 KJMO

June 29, 2024
geometryConcyclic

Problem Statement

ABCDABCD is a convex quadrilateral, both ABC\angle ABC and BCD\angle BCD acute. EE is a point inside ABCDABCD satisfying AE=DEAE=DE, and X,YX, Y are the intersection of ADAD and CE,BECE, BE respectively, but not X=AX=A or Y=DY=D. If ABEXABEX and CDEYCDEY are both inscribed quadrilaterals, prove that the distance between EE and the lines AB,BC,CDAB, BC, CD are all equal.