Line Intersections in a Plane

Theorem: Lines in a Plane

For every two distinct [[Straight Line|straight lines]] which lie in the same [[Planes|plane]] there are two possibilities:

  • The lines intersect in a single [[Euclidean Geometry|point]].
  • The lines do not intersect.
Proof

TODO

Definition: Parallel Lines

Two [[Straight Line|straight lines]] are parallel if they lie in the same [[Planes|plane]] but do not [[Line Intersections in a Plane|intersect]].