partition of quadrilateral@@
@There is a quadrilateral.The points (E, F, G, H) are mid points.Point O is the point of intersection.

Move points(A,B,C,D) to find the geometric quality between the blue areas and the area of quadrilateral ABCD.
@You can also move points (A,B,C,D) on CABRI.

Download CABRI‡U data (d45) from here.