Geometry · Parallel Lines & Angle Pairs
Parallel Lines
HSG-CO.C.9
Definition
Lines in the same plane that never intersect and stay an equal distance apart.
Teach it
Where it is taught, with guided notes, practice, homework, an exit ticket and an interactive Teacher Deck.
Examples
- Line m and line n are parallel, written m parallel to n.
- Railroad tracks are a real-world example of parallel lines.
Key rule
Parallel lines are marked with matching arrowheads and never meet.
Memory hook
Same distance apart, forever — never touching.