In order to begin to analyze in depth what obtuse angle means, we must proceed to fully delve into the clarification of the etymological origin of the two words that give it its shape:
-Angle, in the first place, is a term that is identified by having Greek origin. It derives from “ankulos” (crooked), which later derived in the Latin word “angulus”, which already has the meaning of “angle”.
-Obtuso, secondly, has Latin origin. It comes from “obtusus”, which can be translated as “clumsy”, and which is the result of the sum of two clearly differentiated parts: the prefix “ob-“, which means “against”, and the adjective “tusus”, which is synonymous of “beaten.”

The angles They are geometric figures that are formed from two rays that originate from the same vertex, or from two lines that are on the same surface and intersect each other. According to its characteristics, we can differentiate between numerous types of angles.

One of the most common ways to rate angles is by their width. In this framework we find the obtuse angles: these are angles that they measure more than 90º and less than 180º. By example: angles of 92º, 105º, 136º, 161º and 179º.

No less relevant is to determine that an obtuse angle is formed from the union at a vertex of two rays and that there are different ways to measure it. However, among the most frequent is to use a protractor or to resort to using the bevel and square in combination.

This means that the obtuse angles have greater amplitude than the null angles (measuring 0º), the acute angles (greater than 0º and less than 90º) and right angles (90º). On the other hand, they have a smaller amplitude with respect to the plain angles (180º) and the perigonal angles (360º).

Other classifications frame the obtuse angles between the oblique angles (since they are not straight) and the convex angles (they are less than a straight angle).

Different geometric figures have obtuse angles. An example is the obtuse triangle, which has one obtuse angle and two acute angles. The obtuse triangles, in turn, are oblique triangles because they do not have any right angles. Following these classifications, the obtuse triangles can be isosceles (the obtuse angle is formed by two equal sides, while the third is greater) or scalenes (The three sides measure differently, even those that make up the obtuse angle).

Also, it should not be forgotten that the obtuse angle becomes a fundamental pillar of mathematics in general, as well as the right angle and the acute angle.

It is important to know that, on many occasions, obtuse angles are often confused with so-called reflex angles. These have the particularity that they can measure the same as those mentioned above, but differ in that the reflections are formed in what is the outer part of the shape.