Always
YES!!! Always. Quadrilateral are 4 sides 2-dimensional polygons. Of which a parallelogram is one example.
Always. In fact, one method of proving a quadrilateral a rhombus is by first proving it a parallelogram, and then proving two consecutive sides congruent, diagonals bisecting verticies, etc.
a parallelogram will never ever be a rhombus
is sometimes
NEVER!
Always.
Sometimes :)
Always
Always
Always
A trapezoid is always a 4 sided quadrilateral
A kite is always a 4 sided quadrilateral.