Key vocabulary for Lines, Angles, and Parallelism.
Lines on the same plane that are always the same distance apart and never intersect. The symbol is \(||\).
\(l \ || \ m\)
Lines that are in different planes, are not parallel, and do not intersect.
The red and blue lines are skew.
A line that intersects two or more other lines at different points.
The red line is the transversal.
Angles in the same relative position at each intersection (e.g., top-left).
Example: \( \angle 1 \) and \( \angle 5 \)
Angles on opposite sides of the transversal and inside the other two lines.
Example: \( \angle 3 \) and \( \angle 6 \)
Angles on opposite sides of the transversal and outside the other two lines.
Example: \( \angle 1 \) and \( \angle 8 \)
Angles on the same side of the transversal and inside the other two lines.
Example: \( \angle 3 \) and \( \angle 5 \)
The reverse of a theorem. Used to prove lines are parallel.
Theorem: Parallel Lines \(\rightarrow\) Congruent Angles
Converse: Congruent Angles \(\rightarrow\) Parallel Lines