  In this paper the concept of homothetic parallelogram is introduced. This
concept is a generalization of Varignon's and Wittenbauer's parallelograms of
an arbitrary quadrangle, whose diagonals are not parallel. A formula for the
area and perimeter of a homothetic parallelogram for the case when quadrangles
are not crossed is obtained. The fact that homothetic parallelograms are
similar to one another and are in perspective from diagonals intersection point
is proved.

History and Overview;Metric Geometry