Newton line

When Newton - Straight is defined as the line that runs in a convex quadrilateral that is not a parallelogram through the midpoints of the two diagonals. Parallelograms must be excluded in this definition, as the midpoints of the diagonals coincide with parallelograms and therefore not a straight line to define.

The two routes that connect the midpoints of opposite sides in a convex quadrilateral intersect at a point which lies on the Newton line. If the convex quadrilateral beyond a tangent quadrilateral, then there is, by the theorem of Newton, the center of the inscribed circle also on the Newton line.