# Thread: Uniqueness of a parallel line?

1. ## Uniqueness of a parallel line?

Prove: Through a given external point, there is exactly one line parallel to a given line.
???

2. Originally Posted by Kaloda
Prove: Through a given external point, there is exactly one line parallel to a given line.???
That may or may not be a true statement.
It all depends upon which axion system is in use.
What set of axioms are you given.