Question

The floors in an apartment building belong to different ____.

Answer 1

 They're analogous to planes, but obviously not planes, since they have three dimensions. 

A point would be a person in the building. 

A segment would be a hallway or elevator shaft. 

I can't think of anything that would be analogous to a ray.

Answer 2

Sections is what I would say. Sorry if it isn't correct.