Under this topic, following properties are discussed :
Property 1 = Sum of Two Sides of the Triangle is Always Greater than the Third Side.
Property 2 = Angle Sum Property.
Property 3 = Angles opposite to equal sides of a triangle are equal
Property 4 = Angle opposite to longer side is greater
Property 5 = Pythagoras Theorem or Pythagoras Property
Property 6 = Exterior Angle Property
Property 7 = Mid point property of Triangle
Porperty 8 = Triangles on same base & between same parallel lines
Explanation of these properties are discussed in detail in the above respective links.
