Lines
Lines: Lines are made up of point and are straight. The arrows on each end of the lines represent that the lines go in both directions and are never stopping.
-To make it short, all lines are straight and extend infinitely in both directions.
-Definition: Two points determine a line.
Parallel Lines
- Definition: parallel lines are two coplanar lines that do not intersect. The symbol for parallel lines is //.
There are six ways to prove parallel lines:
| #1 | If two lines are cut by a transversal such that two alternate interior angles are congruent, the lines are parallel. | 1 |
| #2 | If two lines are cut by a transversal such that two alternate exterior angles are congruent, the lines are parallel. | 2 |
| #3 | If two lines are cut by a transversal such that two corresponding angles are congruent, the lines are parallel | 3 |
| #4 | If two lines cut by a transversal such that two interior angles on the same side of the transversal are supplementary, the lines are parallel. | 4 |
| #5 | If two lines are cut by a transversal such that two exterior angles on the same side of the transversal are supplementary, the lines are parallel. | 5 |
| #6 | If two coplanar lines are perpendicular to the same line, the lines are parallel. | 6 |