Points Lines and Planes A C Lesson 2

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

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

Definitions Cont. . A l B 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 or AB D. The double arrow indicates that the line continues without end in both directions. Next

Definitions Cont. . A B 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. Next

Definitions Cont. . 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. Next

Definitions Cont. . m 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. Next

Practice: Are the following sets of points coplaner? 1. 2. 3. 4. B, C, G, F B, C, D, F A, C, G, E E, F, G, H YES YES or NO Next

Practice: • U • V Are the following sets of points collinear? 1. 2. 3. 4. S, T, Q S, T, V T, R, Q U, R, T YES YES or NO Next