Two quadrilaterals@@
Point Eis Middle point of AB. Point F is Middle point of BC. Point G is Middle point of CD. Point H is Middle point of DA.

What the geometric quality is there between the area of Quadrilateral ABCD and the area of Quadrilateral EFGH ?
@You can also move point A,B,C,D on CABRI.

Download CABRI‡U data (d73) from here.