Basic Geometry Terms Flashcards
Collinear Points
Three or more points that belong to the same line
Line segment
A set of two points and all of the points between them
Ray
A set of points consisting of a fixed point of a line and all the points of the line on the same side of the fixed point
Opposite rays
Two rays of the same line that have common endpoint and no other point in common
Angle
A set of points consisting of the union of two disctint non-collinear rays with a common endpoint.
Congruent line segment
Line segments that are equal in measure
Congruent angles
Angles that are equal in measure
Midpoint
The point of a line segment that forms two congruent segments
Line segment bisector
Line, line segment, or ray that intersects that line segment at its midpoint.
Right angle
An angle measuring 90 degrees.
Acute angle
An angle whose measure is less than 90 degrees but greater than 0 degrees
Obtuse angle
An angle whose measure is more than 90 degrees but less than 180 degrees.
Complementary angles
Two angles, the sum whose measure is 90 degrees
Supplementary angles
Two angles, the sum of whose measure is 180 degrees
Intersecting lines
Two lines that have a point in common
Concurrent lines
Three or more lines that contain the same point
Parallel lines
Two lines that lie in the same plane and do not intersect
Perpendicular lines
Two lines that intersect and form a right angle
Angle bisector
A ray (or part of a line) whose endpoint is the vertex of the angle and that forms two congruent angles.
Adjacent angles
Two angles in the same plane that share a common vertex and a common ray, but no other points.
Vertical angles
A pair of angles that share a single vertex but open in opposite directions
Linear Pair
Two adjacent angles such that their non-common rays are mutually opposite form a linear pair
