Straight Angle
Lesson Objective
In this lesson, we will learn about straight angle.
About This Lesson
After knowing what are obtuse angles, we will now learn:
 What is a straight angle.
 See some examples on identifying it.
The study tips below will give you a short summary and it can be used to recall the properties of this angle.
The math video below will explain more in depth about this angle. Furthermore, it will show some examples to identify this angle so that you can understand this lesson better.
Study Tips
Tip #1
If an angle is exactly 180°, it is a straight angle. The picture below shows some examples:
Math Video
Lesson Video
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Straight Angles from MathExpression.com on Vimeo.

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00:00:03.200
In this lesson, we will learn about this type of angle.
00:00:08.120
Let's take a look at this angle.
00:00:11.200
In the previous lesson, we learned that an obtuse angle is always more than 90 degrees, and less than 180 degrees.
00:00:20.210
What happens, when the angle becomes 180 degrees?
00:00:26.140
When the angle becomes 180 degrees, it is called a str. angle.
00:00:32.230
To emphasize, str. angle is an angle that is equals to 180 degrees.
00:00:40.090
Let's see some examples.
00:00:43.130
Is this a str. angle?
00:00:48.030
Yes! It is.
00:00:51.210
How about this angle?
00:00:55.140
Again, this is a str. angle.
00:00:59.240
Next example, is this a str. angle?
00:01:05.030
Clearly, this angle is not equals to 180 degrees.
00:01:10.160
Hence, this is not a str. angle
00:01:15.220
That is all for this lesson.
Practice Questions & More
Multiple Choice Questions (MCQ)
Now, let's try some MCQ questions to understand this lesson better.
You can start by going through the series of questions on straight angle or pick your choice of question below.
 Question 1 on identifying this type of angle.
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