What Types of Angles There Are

An angle is formed from 2 rays or lines that share a common endpoint. There are different types of angles based on measurements or rotations, including obtuse, right, reflex, straight, positive, negative, and more.

5-Minute Crafts will help you figure out how to tell these different angles apart.

I. Types of angles based on measurement

Acute angle

An acute angle is an angle that is less than 90°. It’s formed when 2 rays or lines intersect at a vertex. For example, 20, 30, 45, and 60-degree angles are considered acute.

Right angle

It’s also known as 90° angle. The right angle is formed when 2 straight lines or rays are perpendicular to each other at the intersection (the angle between them equals exactly 90°). If you want to represent this angle as a symbol, use “∟.”

Obtuse angle

An obtuse angle is an angle that is greater than 90° but less than 180°. For example, 100, 130, 145, and 165-degree angles are obtuse ones.

Straight angle

It is also known as a flat angle and represents a straight line. If the angle formed between 2 rays is exactly 180°, then it’s called a straight angle. It can be made up of 2 right angles of 2 rays that face opposite directions.

Reflex angle

It is an angle that is greater than 180° and less than 360°.

200, 250, and 310-degree angles are considered reflex angles. For example, in an original circular pizza, if we cut a small slice (or 2) and remove them, then the remaining part of the pizza represents a reflex angle.

Full rotation angle

A full rotation angle is 360°. An arm of such an angle goes on a complete rotation. You also can say “doing a 360,” which means spinning around completely, once.

II. Types of angles based on rotation

• Angles that are turned from the base in the anti-clockwise direction are called positive.
• Negative angles are rotated from the base in the clockwise direction.