What are Different Types of Triangles?
TRIANGLES
This lesson covers the following types of triangles:
1. Isosceles Triangles
A triangle that has two equal sides is an isosceles triangle.
![isosceles triangles](/images/notes/isosceles_triangles.png)
Each triangle above has two equal sides.
Hence, they are all isosceles triangles.
Hence, they are all isosceles triangles.
We show two or more equal sides by putting a small slash across them.
Trivia:
If you measure the angles of an isosceles triangle you will notice that the angles opposite its equal sides are equal.
2. Equilateral Triangles
A triangle that has all equal sides is an equilateral triangle.
![equilateral triangles](/images/notes/equilateral_triangles.png)
Each triangle above has all 3 sides of the same length.
Therefore, they are all equilateral triangles.
Therefore, they are all equilateral triangles.
We show an equilateral triangle by putting a small slash across each of its 3 sides.
Trivia:
If you measure the angles of an equilateral triangle you will notice that each of its angles is equal to 60°.
3. Right-angled Triangles
A right-angled triangle, as the name suggests, is a triangle that has one angle that is equal to 90°.
![right angled triangles](/images/notes/right_angled_triangles.png)
Each triangle above has one angle that is a right angle, that is, 90°.
So, they are all right-angled triangles.
![right angled triangles](/images/notes/right_angled_triangles.png)
Each triangle above has one angle that is a right angle, that is, 90°.
So, they are all right-angled triangles.
Trivia:
If you measure the other two angles of a right-angled triangle you will notice that their sum is equal to 90°.