GEOMETRYHELP

Name the segments and rays in the figure.

The labeled points in the figure are A, B, and C.

A segment is a part of a line consisting of two endpoints and all points between them. A segment is named by its two endpoints. So the segments are BA (or AB) and BC (or CB).

A ray is a part of a line consisting of one endpoint and all the points of the line on one side of that endpoint. A ray is named by its endpoint first, followed by any other point on the ray. So the rays areBA and BC.

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Segments, Rays, Parallel Lines and PlanesLESSON 1-4

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GEOMETRYHELP

Use the figure below. Name all segments that

are parallel to AE. Name all segments that are skew to AE.

Parallel segments lie in the same plane, and the lines that contain them do not intersect. The three segments in the figure above that are parallel to AE are BF, CG, and DH.

Skew lines are lines that do not lie in the same plane. The four lines in the figure that do not lie in the same plane as AE are BC, CD, FG, and GH.

Segments, Rays, Parallel Lines and PlanesLESSON 1-4

Additional Examples

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GEOMETRYHELP

Planes are parallel if they do not intersect. If the walls of your classroom are vertical, opposite walls are parts of parallel planes. If the ceiling and floor of the classroom are level, they are parts of parallel planes.

Identify a pair of parallel planes in your classroom.

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Segments, Rays, Parallel Lines and PlanesLESSON 1-4

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