Question

The base of a cube is parallel to the horizon. If the cube is cut by a plane to form a cross section, under what circumstances would it be possible for the cross section to be a non rectangular parallelagram?

Answer 1

A non-rectangular parallelogram is formed when the circumstance is that the plane that cuts the cube makes an acute angle to the base of the cube and intersects three vertical faces.

Answer 2

You can get a parallelogram when the plane cuts opposite faces and is not parallel to any edge.