1. 1-5 Postulates and Theorems Relating to Points, Lines, and Planes.
Postulates 5 – 9 deal with the way points, lines, and planes relate.
1) Postulate 5
- A line contains at least 2 points
- A plane contains at least 3 points not all in a line.
- Space contains at least 4 points not all in one plane.

2. 2) Postulate 6
Through any 2 points there is exactly one line.
3) Postulate 7
Through any noncollinear points there is exactly one plane.
4) Postulate 8
If 2 points are in a plane, then the line containing them is in the plane.

3. 5) Postulate 9
If two planes intersect, then their intersection is a line.
B) Theorem – are important statements that are proved.
1) Theorem 1-1
If two lines intersect, then they intersect in exactly one point.

4. 2) Theorem 1-2
Through a line and a point not in the line there is exactly one plane.
3) Theorem 1-3
If two lines intersect, then exactly one plane contains the lines.