# Angle in Dictionary

Angle is a concept of Geometry to refer to the space between the intersection of two lines that start from the same point or vertex, and that is measured in degrees.

The word comes from the Latin angŭlus, and is in turn from the Greek ἀγκύλος, which means “hunched over”.

In everyday use, the word angle can also be used as a synonym for corner (in the sense of the incoming angle), for example: “At what angle of the room do you prefer to put the sofa?”; corner or edge: “Beware of the angles of the table: you can hit yourself”; as well as from the point of view: “Have you already assessed the situation from all angles?”

## Types of angles

### According to its opening in degrees

 Null angle It is that formed by two lines that coincide at its vertex and at its ends, therefore, its opening is 0 °. Acute angle It is one with a vertex opening greater than 0 ° and less than 90 °. Right angle It is made up of two semi-lines whose vertex opening is 90 °. Obtuse angle It is one whose vertex opening is greater than 90 ° and less than 180 °. Flat angle It is that constituted by two semi-lines with a 180 ° vertex opening. Oblique angle Also called reflex or concave, it is one that has a top opening 180 ° and less than 360 ° Perigonal angle Also called full angle, it is one that has a 360 ° opening.

#### Sum of angles

 Complementary angles It is one that, together with another, adds an opening of 90 °. It may be consecutive angles or not in space, but they will be complementary provided that the sum of the degrees of their angles is 90 °. Supplementary angles It is called one that, together with another, adds an opening of 180 °.