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Collinear

If three or more points all belong to the same line they are said to be collinear

Concurrent

If three or more lines contain the same point, they are said to be concurrent

Between

If B is between A and C,

Then points A, B, C are distinct collinear points and AB + BC = AC

Then points A, B, C are distinct collinear points and AB + BC = AC

Same Side

Points B and C are said to be on the same side of point A if A, B, C are collinear and point A is not between point B and C.

Line Segment

A line segment is a set of two points and all the points between them.

Ray

A Ray is 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

Opposite Rays are two rays of the same line that have a common endpoint and no other point in common.

Angle

An angle is a set of points consisting of the union of 2 rays with a common endpoint (vertex)

Interior

A point P lies in the interior of an angle if there exist two points, one on each ray, neither at the vertex, such that the point P is between said two points.

Congruent Line Segments

Congruent Line Segments are line segments that are equal in measure

Congruent Angles

Congruent Angles are angles that are equal in measure

Midpoint

The midpoint of a line segment is a point of the line segment such that 2 segments formed are congruent.

Line Segment Bisector

A line segment bisector is a line that intersects the line segment at its midpoint.

Right Angle

A right angle is an angle measuring 90 degrees.

Acute Angle

An acute angle is an angle measuring less than 90 degrees but greater than 0 degrees

Obtuse Angle

An obtuse angle is an angle measuring greater than 90 degrees but less than 180 degrees

Complementary Angles

Complementary Angles are 2 angles the sum of whose measures is 90 degrees.

Supplementary Angles

Supplementary Angles are 2 angles the sum of whose measuring 180 degrees

intersect

Two lines are said to intersect of they have a point in common

Perpendicular Lines

Perpendicular Lines are 2 lines that intersect and forms a right angle

Angle Bisector

An angle bisector is a ray whose endpoint is the vertex of the angle and that forms 2 congruent angles

Reversed Midpoint

A point of the line segment that forms 2 congruent segments is the midpoint of the line segment

Reversed line segment bisector

A line that intersects the midpoint of a line segment is a line segment bisector

Reversed right angle

A angle whose measure is 90 degrees is a right angle

Reversed angle bisector

A ray whose endpoint is the vertex of the angle and that forms two congruent angles is an angle bisector.

Reversed congruent angle

Angles that are equal in measure are congruent

Reversed congruent line segments

Line segments that are equal in measure are congruent

Adjacent Angles

Adjacent angles are two angles in the same plane that share a common vertex and a common ray but share no other points.

Linear Pair

Angles that form a linear pair are 2 adjacent angles such that their non-common rays are mutually opposite.