1. Chapter 1Section 1 - Points and Lines in the Plane 1 Chapter 1 Exploring Geometry: Points, Lines, and Angles in the Plane Section 1 Points and Lines in the Plane Objectives: Students will be able to identify and model endpoints, line segments, lines, rays and collinear points.

2. Chapter 1Section 1 - Points and Lines in the Plane 2 Points  A point represents a location.  A point has no size and is represented by a dot.  A point is named by an uppercase letter. A B Points A and B.

3. Chapter 1Section 1 - Points and Lines in the Plane 3 Line  A line is made up of an infinite number of points, and extends endlessly in opposite directions.  A line can be named by two points on the line Line AB, BA, A B l or Line l. or by a single lowercase script letter.

4. Chapter 1Section 1 - Points and Lines in the Plane 4 Example 1 Name the line in seven different ways. J L m K Answer: The line can be named as line m. There are three points on the line. Any two of the points can be used to name the line. JK, JL, KJ, KL, LJ, LK

5. Chapter 1Section 1 - Points and Lines in the Plane 5 Collinear noncollinear points collinear points  Points that lie on the same line are called collinear.

6. Chapter 1Section 1 - Points and Lines in the Plane 6 Example 2 Which three points are collinear? A B C D F E Answer: Points A, D, and F are collinear. H G

7. Chapter 1Section 1 - Points and Lines in the Plane 7  A plane is a flat surface, with no thickness, that extends in all directions without end.  A plane can be named by three noncollinear points, Plane Plane ABC C B A or by a single capital script letter. P or Plane P.

8. Chapter 1Section 1 - Points and Lines in the Plane 8 Line Segment  A line segment is part of a line that has a fixed length. It consists of two endpoints and all points between them.  A segment is named by its endpoints. B A Segment AB or Segment BA

9. Chapter 1Section 1 - Points and Lines in the Plane 9 Example 3 Draw and name all of the line segments between points A, B, and C. C B A Segment AB, AC, and BC.

10. Chapter 1Section 1 - Points and Lines in the Plane 10 Ray  A ray is a part of a line that has one endpoint and extends endlessly in one direction.  A ray is named by its endpoint and one other point on the ray. A B C AB AC Read: Ray AB or Ray AC.