Did you know what a triangle is? And what are the different **types of triangles** that exist in mathematics. If you are unaware of exact definition of triangle and **classification of triangles** then read this article. I will make you to understand the concept of triangle and **types of triangles** in a better and easy manner.

**What is the definition of a triangle?** A triangle is a basically, a polygon which is bounded by the three line segments. We can also define a triangle in another way that is a triangle is simple closed figure bounded by line segments. Below is the example for representation of triangle and its important terms.

Note:

A triangle contains of three line segments i.e. PQ, QR and RP.

A triangle contains of three angles i.e. angles P, Q and R.

The three angles and three line segments of triangle are called as elements of a triangle.

**There are totally 7 types of triangles are there in geometry those are mentioned below:**

- Equilateral triangle.
- Isosceles triangle.
- Scalene triangle.
- Acute angled triangle.
- Right angled triangle.
- Obtuse angled triangle.
- Equiangular triangle.

Now let us classify the above 7 types of triangles based on sides and angles.

**Types of triangles based on sides:**

Based on sides triangles are classified into three types. They are

- Equilateral triangle.
- Isosceles triangle.
- Scalene triangle.

**Equilateral triangle:**

In a given triangle, if all the three sides of a triangle are equal in length then it is called equilateral triangle.

If you observe the above triangle it’s all sides i.e. PQ = QR = RP = 2cm. so it is called as equilateral triangle.

**Isosceles triangle:**

In a given triangle, if any two sides of a triangle are equal then it is called isosceles triangle.

In the above triangle, we can observe that the sides PQ and QR are equal in length that is both are equal to 5cm. so it is called as isosceles triangle.

**Scalene triangle:**

In a given triangle, if all the three sides are of different length that is no two sides should be equal, then it is called scalene triangle.

From above triangle it is clear that all the three sides are of different length. So it is called scalene triangle.

**Types of triangles based on angles:**

Based on angles the triangles are classified mainly four types. They are

Acute angled triangle.

Right angled triangle.

Obtuse angled triangle.

Equiangular triangle.

**Acute angled triangle:**

In a given triangle, if all the three angles of a triangle are acute angles then it is called as acute angled triangle.

In the above triangle angles P, Q, R are acute angles so it is called acute angled triangle.

**Right angled triangle:**

In a given triangle, if any one of the angles is equal to 90° then it is called right angled triangle.

In the above triangle, angle Q = 90° so it is called right angled triangle.

**Obtuse angled triangle:**

In a given triangle, if one of the angle of a triangle is obtuse angle then it is called obtuse angled triangle.

In the above triangle angle Q is equal to 120° so it is called obtuse angled triangle.

**Equiangular triangle:**

In the given triangle, if all the three angles of a triangle are equal then it is called equiangular triangle.

In the above triangle we can observe that all the angles are equal so it is equiangular triangle.

These are the **different types of triangles** based on angles and sides of triangles.

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