A triangle is a three-sided polygon which has 3 vertices and 3 sides enclosing 3 angles. The sum of interior angles in a triangle is 180 degrees. Having learnt that, in this article, we introduce you to two special types of triangles- equilateral and isosceles triangle.

**Isosceles Triangle**

Isosceles triangle is a triangle which comprises of 2 equal sides, regardless of direction of the apex of the triangle points. Isosceles triangles have their application in determing the angles. In the isosceles triangle ABC, AB = AC. Similarly, in triangle PQR, PQ = PR. Vertices A and P are known as peaks and BC and QR (unequal sides) are known as the base of the isosceles triangle. Some of its properties are:

- It has two equal sides.
- It has two equal angles, that is, the base angles.
- When the third angle is 90 degrees, it is called a right isosceles triangle.
- The altitude from the apex to the base bisects the angle at the apex.

**Equilateral Triangle**

An equilateral triangle is the one in which all the three sides are equal. It is a special case of the isosceles triangle where the third side is also equal. In the triangle ABC, AB = BC = CA. Properties of an equilateral triangle are:

- It has 3 equal sides.
- It has 3 equal angles.
- Since the sum of the interior angles is 180 degrees, every angle of an equilateral triangle is 60 degrees.
- It is a regular polygon with 3 sides.
- The altitude and median from a vertex is the same single line.
- The ortho-centre and centroid of the triangle is the same point.

To learn more about the special triangles and their properties, download Byju’s- The Learning App.