Obtuse angle


In the area of ​​mathematics, mainly in geometry , angles are formed by two rays or lines that begin at the same point or that meet by sharing the same end point . Angle measures the number of turns between the two arms or sides of an angle and is generally measured in degrees or radians . Where the two rays cross or meet is known as a vertex . In geometry, it is very important to know the correct way to identify obtuse angles because when the angles have measures greater than 90°, it is easier to visually identify the type of angles when they are within a plane or in everyday life .


What is the obtuse angle?

The obtuse angle is an angle that measures more than 90 ° but at the same time measures less than 180 °.  It is formed from the union that occurs at a vertex of two rays and has different ways of being measured.

  • Definition
  • features
  • How much is an obtuse angle
  • Triangle with obtuse angle
  • What objects form an obtuse angle
  • Examples


To find out about the definition of an obtuse angle, it is also important to know its etymology . The word “angle” comes from the Latin word angulus , which means ” corner “. It is also related to the Greek word ankylοs meaning “crooked, curved” and the English word “ankle . ” Both Greek and English words come from the Proto-Indo-European root “ank-“ which means “to bend” or “to bow . 


The obtuse angles are the angles that are formed in the same way that the acute or right angles do, in other words, by means of two rays that are joined at a vertex . However, they are also different from them to the extent that they possess. The obtuse angles then refer to the angles that measure more than 90º and less than 180º.


The main characteristics of the obtuse angle are the following:

  • The obtuse angles are those angles that have measures between 90º and 180º.
  • This type of angle can be qualified depending on its amplitude .
  • The obtuse angles are formed from the union that occurs in a vertex of two rays
  • They can be measured by means of a protractor or they can also be used in combination with the gauge and the square.
  • The obtuse angles have a greater amplitude .
  • Some of the classifications place obtuse angles between oblique angles , this because they are not right and convex angles because they are less than a straight angle .

How much is an obtuse angle

We can say that an obtuse angle is any angle that measures more than 90 degrees but less than 180 degrees , with this we mean that it is the angle that does not measure more than 90 but does not go beyond 180 degrees, being at an intermediate point between the 90 and 180 degrees.

Triangle with obtuse angle

The triangle that has an obtuse angle is known by the name of an obtuse triangle and is that triangle that has an obtuse angle, by this we mean that it has an angle that measures more than 90 ° . Of the three interior angles that the obtuse triangle has, therefore, one of them must be obtuse , while the other two angles that the triangle has will then be acute , that is, angles that measure less than 90 °.

The obtuse triangles can be considered as oblique triangles this because none of their internal angles is considered a right angle . Acute triangles , those with three acute angles, are located within this same rating. If the triangle has a right angle , on the contrary, it is called a right triangle .

It is also important to keep in mind that obtuse triangles can be included in other sets depending on the characteristics of their sides . The obtuse triangle that has two sides that measure the same and a third side that is different is an isosceles triangle . If the obtuse triangle has three sides that are different, all of them with different measures, then we are talking about a scalene triangle .

What objects form an obtuse angle

The obtuse angle can be found in different objects in daily life, among them we can mention:

  • A compass
  • a fan
  • a classical dancer

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