Consider a regular octahedron ABCDEF with lower vertex E, upper vertex F, middle cross-section ABCD, midpoint M and circumscribed sphere k. Further, let X be an arbitrary point inside the face ABF. Let the line EX intersect k in E and Z, and the plane ABCD in Y.
Show that ∢EMZ=∢EYF. geometry3D geometryoctahedronspheregeometry proposed