Math

Proving lines parallel.

Definition

Methods to prove two lines are parallel using angle relationships formed by a transversal. If corresponding angles are equal, alternate interior angles are equal, or co-interior angles are supplementary, the lines are parallel.

Examples

Real-world.

  • 1 If alternate interior angles measure 55° each, the lines are parallel
  • 2 If corresponding angles are both 110°, the lines are parallel
  • 3 If co-interior (same-side interior) angles sum to 180°, the lines are parallel
Studied in

1 unit use this concept.