**If you are interested in learning more about other topics related to angles, you can check out one of the following articles:**

- Angle Notation
- Sides, Vertices, and Angles
- Bisector
- Right Angle
- Obtuse Angle
- Straight Angle
- Adjacent Angles
- Vertically Opposite Angles
- Alternate Angles
- Corresponding Angles
- Sum of the Angles of a Triangle
- Sum of the Angles of a Polygon
- Sum and Difference of Angles

**On the** **Tutorela**** website, you will find a wide variety of articles about mathematics**

**What is an angle?**

An angle is the opening that occurs between two lines that join from a vertex. Angles can be measured in degrees or radians.

**What is the classification of angles according to their measure?**

Angles are classified into 6 types according to their measure:

- Acute angle
- Right angle
- Obtuse angle
- Straight angle
- Reflex angle
- Perigon angle or also called complete angle

**What is an acute angle?**

The acute angle is the narrowest angle of all according to its measure. In this case, an acute angle is one that measures less than $90^o$

**Which of the following angles has a measure less than** **$90^o$**** degrees?**

A) Angle of $200^o$

B) Angle of $160^o$

C) Angle of $30^o$

**Answer:** In this case, option C is the angle that corresponds to an angle less than $90^o$, that is, it is an acute angle.