1. Points, Lines, and Planes Lesson 2a C  B  A  l  R  S Next

2. I. Point A. Has no size--think of a dot (  ) B. Named and labeled by capital letters Examples: A  C  B  Definitions: Next

3. II. Line A. Has an infinite set of points B. Has no thickness C. A line is named by a lower case letter or by any 2 points on the line. l  A  B D. The double arrow indicates that the line continues without end in both directions. line l or AB Definitions Cont.... Next

4. III. Line Segment A. A part of a line consisting of two endpoints and all the points between them. B. In drawings, line segments are usually named with capital letters representing the endpoints. C.For example, the line segment above could be named Segment AB or AB. AB Definitions Cont.... Next

5. IV. Plane A. A plane is also an infinite set of points. B. Think of flatness as suggested by a table top extending in all directions without boundaries. C. Also has no thickness. D. Named and labeled by a capital letter - - or by three points not on the same line. Definitions Cont.... Next

6. V. Space is the set of all points. VI. Collinear points are points that lie on the same line. Noncollinear points are points that do not lie on the same line. VII. Coplanar points are points that lie on the same plane. Noncoplanar points are points that do not lie on the same plane. Definitions Cont....      m       Next

7. Are the following sets of points coplaner? 1.B,C,G,F 2.B,C,D,F 3.A,C,G,E 4.E,F,G,H YESYES or NONO YESYES or NONO YESYES or NONO YESYES or NONO Practice: Next

8. V Practice: Are the following sets of points collinear? 1.S,T,Q 2.S,T,V 3.T,R,Q 4.U,R,T U Next YESYES or NONO YESYES or NONO YESYES or NONO YESYES or NONO