S. Property (iii) is called the triangle inequality.

Concept: Right-angled Triangles and Pythagoras Property.

…these properties is called the triangle inequality.

This follows directly from the triangle inequality.

The third property is known as the triangle inequality.

This is an immediate consequence of the triangle inequality.

The only one which is not obvious is the triangle inequality.

c) d(a,c) has to be smaller or equal than d(a,b)+d(b,c) (triangle un-equation)

…these properties is called the triangle inequality.

(Check that this satisfies the triangle inequality.)

consequence of the symmetry property and the triangle inequality.

This is an immediate consequence of the triangle inequality.