Parallel Lines
Parallel lines never intersect and maintain a constant distance apart, and understanding their properties with transversals is fundamental t
Core concept
Parallel lines are lines in the same plane that never meet, no matter how far they are extended in either direction.
How it works
A transversal is a line that crosses two or more other lines, creating various angle relationships when crossing parallel lines.
Why it matters
When a transversal crosses parallel lines, corresponding angles are equal, and alternate angles are also equal.
Key detail
Co-interior (same-side interior) angles formed by a transversal crossing parallel lines are supplementary, summing to 180°.
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Quick notes
• Parallel lines: never meet, same plane.
• Constant distance apart, extended infinitely.
• Transversal: crosses two or more lines.
• Creates angle relationships with parallel lines.
• Corresponding angles: equal.
• Alternate angles: also equal.
• Co-interior angles: supplementary (sum to 180°).
• These properties solve angle problems.