1. Postulates
Lesson 2.5

2. Postulate – a fundamental rule in Geometry that
is assumed to be true.
Theorem – a rule in Geometry that must be
proved.
C. Proof a logical argument.
i. Paragraph proof
ii. Flow proof
iii. 2-column proof

3. POSTULATES
Through any 2 points there is exactly one line.
Through any 3 points not on the same line, there
there is exactly 1 plane.
A line contains at least 2 points.
A plane contains at least 3 points not on the same line.
If 2 points lie in a plane, then the entire line containing those points lie in that plane.
If 2 lines intersect, then their intersection is exactly one point.
If two planes intersect, then their intersection is a line.

4. THEOREM
If a point is a midpoint, then it divides a segment into 2 congruent parts.