In geometry, an angle is the figure formed by two rays, called the sides of the angle, sharing a common endpoint, called the vertex of the angle. Angles are measured in degrees, minutes, and seconds. A none angle is an angle that measures 0 degrees.
None angles are important in geometry because they are used to define other geometric figures, such as triangles and quadrilaterals. For example, a triangle is a polygon with three sides and three angles. The sum of the interior angles of a triangle is always 180 degrees. If one of the angles of a triangle is a none angle, then the other two angles must each measure 90 degrees.
