4.+Segments,+Rays,+Parallel+Lines+and+Planes

=Segments, Rays, Parallel Lines and Planes= Objective: To identify segments and rays and recognize parallel lines.

Visit Standards page to identify numbers. NCTM Standards: 3 CT Mathematics Standards: 3.1, 3.2
 * Standards **

Many geometric figures, such as squares and angles, are formed by parts of lines called //segments// and //rays//. A segment is the part of a line consisting of two endpoints and all points between them. A ray is the part of a line consisting of one endpoint and all the points of the line on one side of the endpoint. //Oposite rays// are two collinear rays with the same endpoint. Opposite rays always form a line.

Rays must be named with the endpoint first. The second letter can be any point on the line.

Lines that do not intersect may or may not be coplanar. //Parallel lines// are coplanar lines that do not intersect. //Skew lines// are noncoplanar; therefore, they are not parallel and do not intersect. Here is a good description of parallel and skew lines: [].

It is important to remember that both parallel and skew lines never intersect; however, parallel lines are coplanar and skew lines are not. //Parallel planes// are planes that do not intersect. A plane and a line can also be parallel.

Look around the room. What two planes making up the room would hold parallel lines? What two planes would hold skew lines? Edit this wiki and put your answers here.

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