Unit 2 Vocab

point

a location, with no size

line

a straight path that extends in two opposite directions, without end and with no thickness

plane

a flat surface that extends in all direction and has no thickness

collinear points

points that lie on the same line

coplanar

points that lie on the same plane

segment

part of a line that consists of two points, called endpoints, and all points between them

ray

part of a line that consists of one endpoint and all the points on one side of the endpoint

opposite rays

collinear rays that share an endpoint and form a line

midpoint

a point that divides a segment into two congruent segments

segment bisector

a line, segment, ray, or plane that intersects a segment at its midpoint

angle

two rays with the same endpoint

adjacent angles

two coplanar angles that have a common side and vertex but no common interior points

vertical angles

two angles whose sides form two pairs of opposite rays

complementary angles

two angles with measures that have a sum of 90 degrees

supplementary angles

two angles with measures that have a sum of 180 degrees

linear pair

a pairs of adjacent angles whose non-common sides are opposite rays

angle bisector

a ray that divides an angle into two congruent angles

perpendicular lines

lines that intersect and form right angles

perpendicular bisector

a line, segment, or ray that is perpendicular to a segment at its midpoint

counterexample

an example showing that a statement is false

parallel lines

coplanar lines that do not intersect

skew lines

lines that do not lie in the same plane, do not intersect, and are not parallel