Axiom of parallel lines.

An axiom is a truth that does not need to be proven at all. So, the axiom of parallel lines sounds like this. In one plane, where there is already one straight line, through any point that does not belong to the existing straight line, you can draw a straight line, and only one. This straight line will necessarily be parallel to the desired straight line.

Using this axiom, which is also called the property of parallel lines, it is possible to produce other proofs in geometry.

Two more consequences follow from the parallel line axiom:

1) if two lines are parallel to the third line, then such lines will necessarily be parallel to each other;

2) if a straight line passes through one of the parallel straight lines, then it certainly intersects another straight line.