van Aubel's theorem
Sign in to savetheorem that, given a convex quadrilateral, if one constructs a square—external to the quadrilateral—on each side, the 2 line segments between the centers of opposite squares have equal lengths and are orthogonal
theorem that, given a convex quadrilateral, if one constructs a square—external to the quadrilateral—on each side, the 2 line segments between the centers of opposite squares have equal lengths and are orthogonal