Triangle , Types of Triangles

        

Triangle :- A triangle is a simple closed figure consisting of three line segments. 

A closed plane figure bounded by three line segments is called a  triangle.

let A, B  and C  be three non-collinear points.         Then, the figure formed by the three line segments AB, BC and CA is called a triangle ABC,   denoted by ∆ABC.       We denote a triangle by the symbol ∆              In  ∆ABC    has Ø  Three vertices, namely A, B, C Ø  Three sides, namely AB, BC and CA Ø  Three angles namely ∠A,∠B, ∠C Ø  The sides   BC ,  CA   and AB are denoted by a, b and c         In  a triangle ABC, side AB and AC  meet at A.         the remaining side BC is the opposite side of vertex A,   also A is the vertex opposite side BC.         In  ∆ABC,the points A, B and C are called its vertices.         Clearly v  A is the vertex opposite to the side BC. v  B is the vertex opposite to the side CA, and                      C is the vertex opposite to the side AB.                   Types of  Triangles                       Scalene triangle:         If all the three sides of a triangle are of different lengths, then the                                           triangle is called a scalene triangle.         A triangle having  all side of different lengths, is called a Scalene triangle       ABC is  a triangle in which  then  All  the three angles f a scalene triangle are of different measures. Isosceles triangle:- A triangle having two sides of equal length is called an isosceles triangle. If any triangle contains two sides of equal measures, such triangle is called an isosceles triangle. In isosceles triangle, the angles opposite to the  equal sides are equal. In an isosceles triangle the unequal side is called the base of the triangle. The angles contained by the base are called base angles.               The base angles of an isosceles triangle are congruent.              Equilateral triangle:         A  Triangle having all the three sides equal,   is called an equilateral triangle.              The measure of each angle of an equilateral triangle is   600 .