Parallelogram Investigation

The applet below contains a quadrilateral that ALWAYS remains a parallelogram. The purpose of this applet is to help you understand many of the geometric properties a parallelogram has. Some of these properties are unique and only hold true for a parallelogram (and not just any quadrilateral). The questions you need to answer are displayed below this applet.
Use the tools GeoGebra within this applet to investigate the answers to the following questions: 1) Are opposite sides of a parallelogram congruent? 3) Are opposite angles of a parallelogram congruent? 4) Do the diagonals of a parallelogram bisect each other? 5) Does a diagonal of a parallelogram bisect a pair of opposite angles? If so, how many do? 6) Are the diagonals of a parallelogram perpendicular? 7) Are the diagonals of a parallelogram congruent?