Types of Angles  Lessons
Introduction
This page contains the list of lessons on types of angles. It also covers the basics on angles. Each lesson consists of a math video, study tips and practice questions.
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Lesson Description
An angle is formed when two lines diverge from a common point (the vertex). If you are new to angles, you can:
 Learn about the basics on angles by watching the math video below.
After understanding the basics, the list of lessons below will touch on:
 Using the protractor to measure angles.
 Different types of angles.
Introduction Video
The Basics on Angles from MathExpression.com on Vimeo.
Get to know angles better in a fun interactive way by downloading our free Zapzapmath Home Grade 4 and playing Angle Align:
Apple App Store (iOS) 
Google Play (Android)
Math Video Transcript
00:00:04.020
In this lesson, we will learn about the basics on angles.
00:00:09.040
Consider these 2 lines. When these 2 lines meet, an angle is formed.
00:00:17.100
This is the vertex of the angle and these 2 lines are the arms of the angle.
00:00:27.100
Now, this angle has a certain value.
00:00:31.030
This value happens to be 50 degrees.
00:00:35.150
Now, this symbol is the unit for angle. It is called 'degree'.
00:00:42.070
Knowing this, let's rotate this arm, to find out the different values of this angle.
00:00:49.060
Here, we can see that, the lowest value for this angle is 0 degree.
00:00:55.080
Next, let's increase the angle.
00:01:01.110
At this point, we have the angle as 90 degrees.
00:01:06.140
Let's further increase the angle. Now, we have 180 degrees, 270 degrees, finally 360 degrees for a full rotation.
00:01:36.220
Next, let's learn how to name an angle.
00:01:41.190
We can label these 3 vertex as A, B and C respectively.
00:01:52.150
Here, we can see that, this angle is between, A, B, and C.
00:02:04.070
With this, we can write, angle ABC equals to, 60 degrees.
00:02:12.070
Now, if we name it as, angle CBA, it is still the same.
00:02:20.170
Here, note that, the vertex of the angle is always the middle letter.
00:02:27.040
Therefore, we can also write the angle B, equals to 60 degrees provided that, it is not ambiguous.
00:02:37.170
That is all for this lesson.
End of transcript for types of angles
Topic Lessons

Using a Protractor (Measuring Angles)
In this lesson, we will learn how to measure angles using a protractor...

Acute Angles & Right Angle
In this lesson, we will learn what are acute angles and right angle...

Obtuse Angles
In this lesson, we will learn about obtuse angles...

Straight Angle
In this lesson, we will learn about straight angle...

Reflex Angles
In this lesson, we will learn about reflex angles...

Full Angle
In this lesson, we will learn that a 360 degree angle is a full angle...