TRIANGLES

A closed polygon having three sides are called triangles.

We can differentiate triangle on two basis. 

  • According to sides
  • According to angles



  • According to side


  • Scalene Triangle 
 
In Scalene triangle  all sides are unequal. Mathematics Section 



  • Isosceles Triangle
In Isosceles triangles are those triangle which has two side equal and angle opposite to that side are equal.



  • Equilateral Triangles
 Equilateral Triangles are those type of triangle which has all side equal and all angles are also equal.


  • According to angle
 

  • Acute Angled Triangles

 An  Acute Angle Triangle is a different type of triangles in which all its angle is less than 90 degree.

  
  • Obtuse Angled Triangles
 Obtuse Angled Triangle is a triangle which has one angle more than 90 degree from three angles of triangles.


  • Right Angled Triangles
 Right Angled Triangle means which has one angle is 90 degree and other angle are an acute angles.




  • Perimeter of Triangle
 Perimeter of Triangle means to find total distance cover, when we start from point A then complete one round and reach at same point A again.
For example-  In  △ABC  A, B and C are the point of triangle and  let someone be x which is at point A and they start moving from point A to B then B to C and C to A. It again reach at point A. The total distance cover by x is called the perimeter of triangle.


 
  • Area of Triangle

  • For any three sided figure triangle, we find the area using Heron's Formula
Three side of triangle are a, b, and c.  
 S = (a+b+c) /2    where S = Half/Semi perimeter

Area of Triangle ABC



  • If a Triangle is Right Angled Triangle
 In Right  ⊿ABC , Angle  ∠B is 90 degree 


In right angled triangle there is one perpendicular,  base and hypotenuse.
It also follow Pythagoras theorem,
 

If we find the area of right angle triangle ABC




Note - If you get perpendicular in any triangle then you may also apply the above formula to find the area of triangle.



  • Area of Equilateral Triangle
  

In Equilateral triangle all sides are equal. 
Therefore you find the area of equilateral triangle by using the formula-


where a is the side of equilateral triangle

Note - In this triangle you can apply any above two formulas to find the area of triangle but for equilateral triangle there is a unique formula .


  • Area of Isosceles Triangle

 Area of Isosceles triangle-


 First we find the height(perpendicular) from   △ABC  using Pythagoras theorem. 



Therefore , Area of  △ABC