Before looking at different types of angles and their corresponding names, one needs to have a good understanding of degree measure of an angle and how we use it when measuring angle sizes.
At a more basic level, degrees are the general method of measuring the size of angles.
With a standard angle being a specific value of a rotation.
Degrees in a Circle
How to write Degrees
The symbol used for degree measure of an angle is a small circle above the right side of a certain number.
So 50 degrees is written as 50°.
A complete rotation all of the way around a full circle is of size 360°.
A quarter of the way around a circle is of size 90°.
Half way around a circle is 180°, and three quarters around a circle is of size 270°.
Angles of size 40 degrees and 120 degrees inside a circle would look like the following.
As will be viewed later on in the page. Different sized angles have different names to classify them.
It’s also the case that angles don’t only go up to 360° in size.
We can keep going beyond one full rotation of a circle as far as we would like.
The picture below gives a basic example of where an angle of size 400° is shown.
Degree Measure of an Angle Examples
(1.1)
Blue angle: 360° − 295° = 65°
(1.2)
Blue angle: 360° − 130° − 110° = 120°
Types and Names of Angles
Different angle types have different names to identify them.
Below is a selection of some of the most common angle types that can be seen in Math.
Right Angle
A right angle is an angle that is exactly 90° in size.Generally right angles are drawn as a square.
Acute Angle
An acute angle is an angle that is smaller than 90° in total size.
Obtuse Angle
An obtuse angle is an angle that is greater than 90°, but less than 180°.
Straight Angle
A straight angle is an angle that is exactly 180°.Which is the angle we get on a straight line.
Reflex Angle
A reflex angle is an angle where the size is larger than 180°, but smaller than 360° in size.
Adjacent Angles
Adjacent angles are angles that share a common point/vertex, and also a common side, while not overlapping each other.