Geometry beginning with A

Geometry Definitions
Click one of the letters above to go to the page of all terms beginning with that letter.
Acute Angle

An angle whose measure is less than 90º.

Acute angle
Adjacent Angles

Any two angles that share a common side separating the two angles.

Adjacent angle
Alternate Exterior Angles

An angle whose measure is less than 90º.

Alternate exterior angles
Alternate Interior Angles

An angle whose measure is less than 90º.

Alternate interior angles
Angle Bisector

A ray that divides an angle into two equal angles.

Angle bisector
Angles

Two rays that have a common endpoint form an angle.

Angles
Axiom

A statement that is assumed true with no proof. Examples:

  • A line contains at least 2 points.
  • A plane contains at least 3 non-linear points.

Often referred to as a postulate. The words axiom and postulate may be used interchangably.