**Chapter 1.2 Points, Lines, and Planes**

**I) Undefined Terms:**

**A)**

**Point**: a point has no dimension, usually represented by a small dot.

**B) Line**: A line extends in one dimension. It is usally represented by a straight line with two arrowheads to indicate that the line extends without end in two directions.

**C) Plane**: a plane extends in two dimensions, goes on forever.

**D) Collinear Points**: 2 or more points on the same line.

**E) Coplanar Points**: Points that lie on the same plane.

**F) Line Segment**: a segment of a line; consists of 2 endpoints and all points in between.

**G) Ray:**An initial point and all points one side of that point.

**H) Opposite Rays**: 2 rays that form a straight line.

**I) Intersect:**Two or more geometric figures intersect if they have one or more points in common.