#### What Are Angles?

Angles are used in a branch of mathematics, called geometry. This branch involves shapes and different measurements. In geometry, an angle can be defined as the figure that two rays form when they meet at a common endpoint.
An angle can be represented by the symbol ∠. For instance, the angle made by the lines in the diagram can be called ∠AOB.
You can use a protractor to measure an angle. The unit used is called degrees and is represented by a ° sign.
There are many types of angles, and they are used in different ways in math. The types of angles include:
**Acute angles** - Angles below 90° are called acute angles.
**Right angles** - Angles of 90° are called right angles.
**Obtuse angles** - Angles above 90° are called obtuse angles.
**Straight angles** - An angle made by a straight line is of 180° and is called a straight angle.
**Reflex angles** - An angle above 180° is called a reflex angle.
**Complete angles** - An angle of 360° is called a complete angle because it is made by a complete circle.

###### Right, Acute, or Obtuse?

Classify each angle as they are presented to you. Am I the right angle or just a cute angle?