Unit 1: Points, Lines and Planes Vocabulary

plane

A flat surface that goes on forever in two directions; an infinite set of points; it has no thickness and is two dimensional.

segment bisector

A line that divides a segment at its midpoint to form two congruent segments.

perpendicular bisector

A line that passes through the midpoint of a segment and is perpendicular to that segment.

midpoint

A point that divides a segment into two congruent segments.

line

An infinite set of points that goes on forever; it has no thickness and it is one dimensional.

point

It marks a location and is named by a capital letter; it has no thickness and 0 dimension.

skew

Lines that are not parallel and do not intersect.

parallel

Lines that do not intersect but are in the same plane.

endpoint

Marks the end of a line segment or ray.

segment

Part of a line consisting of two end points and all the points between them.

ray

Part of a line that starts at a particular point and extends infinitely in one direction.

noncollinear

Points that do not lie on the same line.

noncoplanar

Points that do not lie on the same plane.

collinear

Points that lie on the same line.

coplanar

Points that lie on the same plane.

congruent segments

Segments that have the same length.

space

The set of all points. It is three dimensional.

intersection

The set of points both figures have in common.

intersecting lines

Two lines that cross at a given point.

perpendicular

Two lines that intersect to form right angles.

opposite rays

Two rays that share a common endpoint but extends in opposite directions and makes a line.