You have probably had the experience of standing in line for a movie ticket, a bus ride, or something for which the demand was so great it was necessary to wait your turn. However, in geometry, there are three types of lines that students should understand.
Intersecting lines
Two or more lines that meet at a point are called
intersecting lines. That point would be on each of these lines. In Figure
1 , lines
l and
m intersect at
Q.
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Figure 1
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Intersecting lines.
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Perpendicular lines
Two lines that intersect and form right angles are called
perpendicular lines. The symbol ⊥ is used to denote perpendicular lines. In Figure
2 , line
l ⊥ line
m.
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Figure 2
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Perpendicular lines.
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Parallel lines
Two lines, both in the same plane, that never intersect are called
parallel lines. Parallel lines remain the same distance apart at all times. The symbol // is used to denote parallel lines. In Figure
3 ,
l //
m.
Fundamental Ideas
Parallel Lines
