**Triangle** – In this articles we discuss about **Triangle**, **Types of triangle**, **properties of triangle**, **Triangle area**, **Triangle perimeter**.

## Triangle

It is a closed geometrical figured enclosed by three line segment and three sides, three vertices and three angles.

### Properties of Triangle

- A closed area formed by joining three non – co linear points is called triangle and the non – co linear points are called vertices.
- Triangle having three side AB, BC, AC.
- In the above picture three vertices are A, B, C and three angle are angle BAC, angle ABC and angle BCA.
- In a triangle sum of the all angle is 180 degree ( BAC + ABC + BCA=180).
- Sum of all (three) exterior angle of a triangle is always 360 degree.
- Any exterior angle of a triangle is equal to the sum of the opposite interior angle.
- One side of a triangle always less than the sum of other two sides (AB < BC + AC).
- Opposite side of the vertices is denoted as small letter of the vertices (A = a, B = b, C = c) .
- The perpendicular bisectors of all three sides of a triangle meet at point at which is called
**circumcenter**, which is equidistant of all the vertices.

## Types of Triangle

**Obtuse Angle Triangle**:- In this type of triangle one of the angle is more than 90 degree.

**Acute Angle Triangle**:-In this type of triangle all three angle are less than 90 degree.

**Right Angle Triangle**:-In this type of triangle one of the angle is 90 degrre.

**Equilateral Triangle**:- In this type of triangle all three side of the triangle is equal and angle of the equilateral triangle is equal as 60 degree.

**Isosceles Triangle**:- In this type of triangle two side s are equal but other side is unequal and opposite angle of equal side is equal.

**Scalene Triangle**:-In this type of triangle All the three side are unequal.