- For any plane in space there exist points belonging to that plane and not belonging to it.
- If two different planes have a common point, they have the common line passing through that point.
- If two different straight lines have a common point, it is possible to draw one and only one plane through these lines.
- For any plane the axioms of plane geometry hold true.
A corollary of these axioms is that through three points, which are not in the same line, there can be drawn one and only one plane. The model illustrates the corollary.