Parallel lines are a fixed distance apart and will never meet, no matter how long they are extended. Lines that are parallel have the same gradient. The graphs above, \(y = 2x + 1\) and \(y = 2x - 2\) ...
It is important to remember other angles rules, such as angles on a straight line add up to 180°, and to recognise angles in parallel lines. Make sure you are confident in applying Pythagoras’ theorem ...