Topic summary

Oblique angle

Extracted from the Wikipedia article Angle.

An angle equal to 0° or not turned is called a zero angle.
An angle smaller than a right angle (less than 90°) is called an acute angle.
An angle equal to ⁠1/4⁠ turn (90° or ⁠ $π$ /2⁠ rad) is called a right angle. Two lines that form a right angle are said to be normal, orthogonal, or perpendicular.
An angle larger than a right angle and smaller than a straight angle (between 90° and 180°) is called an obtuse angle ("obtuse" meaning "blunt").
An angle equal to ⁠1/2⁠ turn (180° or $π$ rad) is called a straight angle.
An angle larger than a straight angle but less than 1 turn (between 180° and 360°) is called a reflex angle.
An angle equal to 1 turn (360° or 2 $π$ rad) is called a full angle, complete angle, round angle or perigon.
An angle that is not a multiple of a right angle is called an oblique angle.