Obtuse Triangle

Lesson Icon

Lesson Objective

In this lesson, we will learn about obtuse triangles...

Why icon

About This Lesson

In this lesson, we will:

  • learn what are obtuse triangles.
  • See some examples on identifying them.

The study tips below will give you a short summary on this.

The math video below will explain in depth about this. Furthermore, it will show some examples so that you can understand this lesson better.

obtuse triangle example

Study Tips

Study Tips Icon

Tip #1

When one of the internal angle of a triangle is greater than 90°, this triangle can be called an obtuse triangle. See some examples below:

examples of obtuse triangles

The math video below will explain more...

Math Video

Lesson Icon

Lesson Video

Sponsored Links

Interact and have fun learning of the types of triangles by downloading our Zapzapmath Home Grade 4 app and playing Shape Detective:
Apple App Store (iOS) | Google Play (Android)

Lesson Icon

Math Video Transcript

00:00:03.120
In this lesson, we will learn about obt. triangles (OT).

00:00:08.070
A triangle is an OT, when it has an internal angle that is greater than 90 degrees.

00:00:17.120
Now, to demonstrate this, let's move vertex 'A' to the left

00:00:26.050
Notice that, when the angle at vertex 'B' is greater than 90 degrees, this triangle becomes an OT.

00:00:34.230
Next, let's move this vertex, to the right..

00:00:40.100
Here, we get another OT, when the angle at vertex 'C', is greater than 90 degrees.

00:00:48.120
Let's move vertex 'A'…and vertex 'C'.

00:00:55.220
Again, we get another OT, when the angle at vertex 'A' is greater than 90 degrees.

00:01:04.120
Let's see some examples.

00:01:07.120
Is this an OT?

00:01:12.070
Notice that, this angle is greater than 90 degrees.

00:01:17.010
Therefore, this is an OT.

00:01:21.090
Next example, how about this triangle?

00:01:28.180
In this triangle, there are no angles that are greater than 90 degrees.

00:01:34.100
Hence, this is not an OT.

00:01:38.140
That is all for this lesson.

Practice Questions & More

Practice Icon

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 obtuse trianglesor pick your choice of question below.

Search Icon

Site-Search and Q&A Library

Please feel free to visit the Q&A Library. You can read the Q&As listed in any of the available categories such as Algebra, Graphs, Exponents and more. Also, you can submit math question, share or give comments there.

Practice Icon

Share This Page