Three Sided Polygon - Triangle

Properties	Types / Classification	Perimeter of Equilateral Triangle	Median of Triangle	Interior of a Triangle
Exterior of a Triangle	Altitude of a Triangle	Interior Angles of Triangle	Exterior Angles of Triangle	Interior Opposite Angles of Triangle
Adjacent Interior Angle of Triangle	Congruent Triangles	Area of Triangle	Area of Triangle by Heron's Formula	Construction of Triangle (compass)

Before you study about what is a triangle, you are advised to read What is a Polygon ? "Tri" means Three, so a polygon which have 3 angles is known as Triangle. A Triangle have 3 Sides, 3 Angles and 3 Vertices. In order words: Triangle is a simple closed curved made up of three line segments. In the Above diagram :- Triangle ABC has 3 Sides - AB, BC and CA 3 Angles - ABC, BCA and CAB 3 Vertices - A, B and C In the Above diagram :- Triangle PQR has 3 Sides - PQ, QR and RP 3 Angles - PQR, QRP and RPQ 3 Vertices - P, Q and R