1. Chapter 2.4 Notes: Use Postulates and Diagrams
Goal: You will use postulates involving points, lines, and planes.

2. your notes
axioms
postulates
Theorems

3. Write into our foldable
Point, Line, and Plane Postulates:
Postulate 5:
Through any two points there exists exactly one line.
Postulate 6:
A line contains at least two points.
Postulate 7:
If two lines intersect, then their intersection is exactly one point.

4. Write into our foldable
Postulate 8:
Through any three non-collinear points there exists exactly one plane.
Postulate 9:
A plane contains at least three non-collinear points.
Postulate 10:
If two points lie in a plane, then the line containing them lies in the plane.
Postulate 11:
If two planes intersect, then their intersection is a line.

5. your notes
Ex.1 : State the postulate illustrated by the diagram. a. b. Solution: a. Postulate 8 b. Postulate 7 Ex.2 : State the postulate illustrated by the diagram. a. Postulate 11 b. Which postulates allows you to say that the intersection of line a and line b is a point? Potulate 7

6. your notes Q
W,V,Y
Line b

7. Diagrams Lie!
Reminder: Diagrams are often misleading. Here are some examples.
collinear
Coplanar
BDH H
BHD
Collinear CE CE

8. your notes
perpendicular to a plane
B,C
No symbols