Two lines in a plane never meet, no matter how far they are extended. What term describes their relationship?

• A. Parallel
• B. Intersecting
• C. Similar
• D. Perpendicular

Answer: (A)

Two lines in a plane that never meet are called parallel. This happens because they move in the same direction and stay a constant distance apart, so they never cross no matter how far you extend them. Think of tracks laid side by side: they run the same way, never touch, and keep the same gap between them. In coordinate terms, lines with the same slope (provided they are distinct) are parallel.

This is different from intersecting lines, which cross at a point, and from perpendicular lines, which cross at a right angle. The word similar isn’t used to describe the relationship between two lines.