## 29 terms

### Between

If B is between A and C,

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.

### 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.

### 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.

### 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.

### 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 angle bisector

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

### 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.