Definition MidLineDef (A B : Point) : Figure := 
	fun M : Point => Distance M A = Distance M B.

Lemma CollinearMidLine : forall A B C D M : Point, A <> B -> Distance C A = Distance C B -> Clockwise A B C -> Distance D A = Distance D B -> Clockwise B A D -> Collinear C D M -> Distance M A = Distance M B.