Posted by IB student on .
Two planes that lie in parallel planes are ________. Answers: Always, Never, or Sometimes
I'm having some trouble on this one... I think it's sometimes...?

Geometry Honors (p.2) 
Steve,
sometimes what?
Is there a typo here? The required answer is "always parallel".
actually, the question is illworded. What does it mean for a plane to lie in a plane?
I think they mean polygons, or plane figure, or region which lies in a plane.
Associated with a plane is a normal vector, which is perpendicular to it. Parallel planes have normals which have the same or opposite direction. That is, the normals are parallel.