Parallel Lines
Lines are parallel if they are always the very same distance apart (called "equidistant"), and also will never meet. Just remember:
Always the very same distance apart and never touching.
You are watching: Parallel lines have so much in common
The red heat is parallel come the blue line in each of these examples:
Try that yourself:Pairs that AnglesWhen parallel lines gain crossed by one more line (which is referred to as a Transversal), you have the right to see that countless angles are the same, together in this example: These angles have the right to be made right into pairs the angles which have special names. Click on each surname to see it highlighted: Now play through it here. Try dragging the points, and choosing different angle types. Friend can additionally turn "Parallel" turn off or on: Testing for Parallel LinesSome that those special pairs that angles deserve to be offered to test if present really are parallel:

These lines are parallel, due to the fact that a pair of matching Angles room equal.  
These lines room not parallel, due to the fact that a pair the Consecutive interior Angles carry out not include up to 180° (81° + 101° =182°)  
These currently are parallel, since a pair of alternate Interior Angles space equal 
angle On a right Line Angles approximately a allude Transversal Congruent angle Vertical angle Geometry index