1. 1.2 Points, Lines, and Planes
Chapter 1
1.2 Points, Lines, and Planes

2. Point
A location, represented by a capital letter, has no size.

3. Space
A set of points.

4. Line
A series of points that extends in two opposite directions without end. A B m
Named using:
AB or line m

5. Collinear points Points that lie on the same lineB m C D
Points A, B, and C are collinear
Points A, C and D are noncollinear

6. Plane
It is a flat surface that has no thickness. It contains many lines and extends without end in the directions of all of its lines. It is names either by a single capital letter, or by at least 3 noncollinear points.

7. Coplanar
Points and lines that lie in the same plane are called this

8. Postulate or axiom
An accepted statement of fact.

9. POSTULATES: 1-1: Through any two points there is exactly one line
1-2: If two lines intesect, then they intersect in exactly one point.
1-3: If two planes intersect, then they intersect in exactly one line.
1-4: Through any three noncollinear points, there is exactly one plane.

10. Example 1:
Are the three points collinear? If so, name the line on which they lie.
A, D, E ?
B, C, D ?
A, E, C ?
Name line m in three
other ways. . m A . . G n B C D F E l

11. Example 2 Name the plane represented by each surface of the box.
The bottom
The top
The front
The back
The right side
The left side M A H D N R I T