The properties of a parallelogram:
1. opposite sides are parallel
2. opposite sides are equal in length
3. opposite angles are equal
4. diagonals bisect each other
if XN=NZ and NY=NW, then
XY=WZ and XW=YZ because the corresponding angles are equal = corresponding sides are equal
The opposite sides are parallel as well because the diagonals are equal (the vertical opposite angles are equal)
This was a word pasta but hope this helps