Types of Triangles  Lessons
Introduction
This page contains the list of lessons on types of triangles. It also gives you a quick introduction on triangles. Each lesson consists of a math video, study tips and practice questions.
Sponsored Links
Lesson Description
A triangle is a polygon with three vertices and three sides (edges). It has three internal angles. When we add all the internal angles together, we will definitely get 180°.
The video below will give you a quick introduction to the following types of triangles:
 Acute triangle
 Right triangle
 Obtuse triangle
 Isosceles triangle
 Equilateral triangle
 Scalene triangle
You can learn more about these triangles in the lessons below.
Introduction Video
Math Video Transcript
00:00:03.230
This video is an introduction to types of triangles.
00:00:09.070
A triangle is a polygon, with 3 vertices, and 3 sides.
00:00:17.120
Now, let's have a quick look, at the different triangles.
00:00:23.100
We will learn the details in the upcoming lessons.
00:00:27.240
Now, if we classify triangles by internal angles, this triangle will be an acute triangle.
00:00:35.150
Now, when I move this vertex to the left, we can see that this triangle becomes a right triangle, when the angle at vertex B is 90 degrees.
00:00:47.240
As we move vertex 'A' further to the left, this triangle becomes an obtuse triangle.
00:00:55.180
Now, let's classify triangles, by relative lengths of sides.
00:01:02.000
Let's move this vertex. When this triangle has 2 sides of equal length, it is called an isosceles triangle.
00:01:16.230
Next, if all the sides of the triangle have the same length, it is an equilateral triangle.
00:01:25.050
Let's move the vertex 'A' around. Alright, if none of the sides of the triangle have the same length, it is called a 'scalene' triangle.
00:01:39.190
That is all for the introduction. The lessons below will explain these triangles in detail.
Topic Lessons

Acute Triangle
In this lesson, we will learn about acute triangles...

Right Triangle
In this lesson, we will learn about right triangles...

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

Isosceles Triangle
In this lesson, we will learn about isosceles triangles...

Equilateral Triangle
In this lesson, we will learn about equilateral triangles...

Scalene Triangle
In this lesson, we will learn about scalene triangles...