Postulates Lesson 2.5

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

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.

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