According to scientific definitions, angles are those figures constituted by the conjunction of two lines at a common point or vertex. For an angle to be formed, the lines that are part of the process cannot be parallel to each other since that implies that there is no contact between the two and therefore no common surface is formed between them. As is well known, there are different types of angles and the degree of inclination or its size will depend on the distance that separates the two or more intervening lines in the figure.
When we analyze the word angle from an etymological point of view, we will understand that its meaning in Latin ("corner") is clearly fundamental to define it. One can have numerous items to measure and analyze at an angle, although they all have to work in the plane of the flat dimension to achieve results. The degree of an angle is in this sense one of the main elements that help us to describe and characterize each angle. The radian will also be the unit of each angle that is equal to the length of the angular radius.
Regarding the classification of the different types of angles, we can say that among the main ones we will find right angles (those that measure 90 °), acute angles (less than 90 °) and obtuse angles (greater than 90 °) . On the other hand, we also have flat angles (all those angles that have 180 ° - that is, two right angles superimposed on a surface-). Finally, we must also include in this classification null angles (when there are no angles due to the arrangement of the lines), complete angles (characterized by having 360 °.
Angles can also be classified according to whether they are convex or concave, the first being less than 180 ° and the second, greater.
