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Table of Contents:

**Area of triangle: **[ l×b /2 ]

**Perimeter of Triangle: **[ (a + b + c) ]

**Area of Equilateral Triangle:** [ (Sqrt (3)/4)×(side)² ]

**Area of Triangle SAS (2sides & opposite angle): **[ ½×a×b×SinC ]

**Where,**

l = length

b =breadth

a,b, and c = sides of the triangle

A triangle is a plane figure with straight sides and three angles. All of the interior angles add up to 180 degrees. A triangle is a polygon with three corners or vertices and three sides or edges which are line segments. A triangle with vertices A, B, and C is denoted ABC.

A triangle is a three-sided polygon consisting of three line segments linked end-to-end.

The interior angles of triangle always add up to 180 degrees

The exterior angles of triangle always add up to 360 degrees

**There are seven types of triangles:**

- Isosceles triangle
- Equilateral triangle
- Scalene triangle
- Right angle triangle
- Obtuse triangle
- Acute triangle
- Equiangular

__Examples__:

**Calculate the area of a triangle with the given length as 3 and breadth as 4 cm.**

**Area = **[ l×b /2 ]= (3*4/2) = 12/2 =** 6**

**Calculate the Perimeter of triangle with the given sides as 3, 4 and 5 cm**

**Perimeter** = a+b+c = 3+4+5 = **12**

**Calculate the area of an equilateral triangle with the given side length as 4 cm**

**Area **=** **[ (Sqrt (3)/4)×(side)² ] = [ (sqrt(3)/4 *(4)2 ] = 1.73/4 *16 = 0.4325 *16 =** 6.92**