We see that by implication, no intersection of lines will take place when the sum of the measures of the interior angles on the same side of the falling line is exactly `180°.`
There are several equivalent versions of this postulate. One of them is ‘Playfair’s Axiom’, as stated below
‘For every line l and for every point P not lying on l, there exists a unique line m passing through P and parallel to l’.
From Fig. 5.11, you can see that of all the lines passing through the point P, only line m is parallel to line l.
This result can also be stated in the following form:
`bb"Two distinct intersecting lines cannot be parallel to the same line."`