MathDB
A funny angle equality in a rigid square configuration

Source: Czech-Polish-Slovak Junior Match 2024, I-3

May 29, 2024
geometrygeometry proposed

Problem Statement

Let ABCDABCD be a convex quadrilateral with AB=BD=DCAB=BD=DC and ABBDDCAB \perp BD \perp DC. Let MM be the midpoint of segment BCBC. Show that BAM+DCA=45\angle BAM+\angle DCA=45^\circ.