Points, Lines, Segments, and Rays Lesson 15-1

Points A point is a location in space. It has no size. It is named by a capital letter. . Read it as: “Point A” Write it as: “A” A

Lines A line is a series of points that extends in two opposing directions without end. Lines have no thickness. Q S Read it as: “Line QS” or “Line SQ” Write it as: QS or SQ

Segments R B A segment is a part of a line with two endpoints. Read it as: “Segment RB” or “Segment BR” Write it as: RB or BR

Rays A ray consists of an endpoint and all the points of a line on one side of the endpoint. C D Read it as: “Ray CD” (the order does matter) Write it as: CD

Planes A plane is a flat surface with no thickness that extends without end in all directions. Intersecting lines are lines that cross (intersect) at exactly one point. Parallel lines are lines that do not cross (they have no points in common). Skew lines are not parallel and they do not intersect. They lie in different planes.

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