1.1: Understanding Points, Lines, and Planes
Definitions:
Point - Names a location and has no size it is represented by a dot.
Line- A straight path that has no thickness and extends forever.
Plane - A flat surface that has no thickness and extends forever.
Segment - The part of a line consisting of two points and all points between them.
Endpoint - A point at one end of a segment or starting point of a ray.
Ray - A part of a line that starts at an endpoint and extends forever in one direction.
Opposite Rays - Two rays that have a common endpoint and form a line.
Postulates:
1. Through any two points there is exactly one line.
2. Through any three noncollinear points there is exactly one plane containing them.
3. If two points lie in a plane, then the line containing those points lies in the plane.
Examples:
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