Anne's theorem
Anne's theorem, named after the French mathematician Pierre-Leon Anne, is a statement from Euclidean geometry, which describes an equality of certain areas within a convex quadrilateral.
Specifically, it states:
For a parallelogram the Newton line does not exist since both midpoints of the diagonals coincide with point of intersection of the diagonals. Moreover the area identity of the theorem holds in this case for any inner point of the quadrilateral.
The converse of Anne's theorem is true as well, that is for any point on the Newton line which is an inner point of the quadrilateral, the area identity holds.
