6. Sides of a triangle

Perimeter of a Triangle
    The sum of the lengths of the sides of a triangle is called its Perimeter.

In ∆ AC = b, BC = a, AB = c then perimeter is BC + CA + AB = a + b + c 

TRIANGULAR INEQUALITY PROPERTY

The sum of the lengths of any two sides of a triangle is always greater than the third side.
        AB + BC > AC
        AB + AC > BC
        AC + BC > AB
The difference between the length of any two sides of a triangle is smaller than the length of the third side.
        AB – BC < CA
        BC – CA < AB
        CA – AB < BC

Example

XY + YZ > XZ
        3 + 4 > 5
similary YZ + XZ > XY
        4 + 5 > 3
 similary XY + XZ > YZ
        3 + 5 > 4