- A straight line may be drawn between any two points.
- Any terminated straight line may be extended indefinitely.
- A circle may be drawn with any given point as center and any given radius.
- All right angles are equal.
- If two straight lines in a plane are met by another line, and if the sum of the internal angles on one side is less than two right angles, then the straight lines will meet if extended sufficiently on the side on which the sum of the angles is less than two right angles.