What lines are parallel?

Answer 1

Parallel lines are lines which share the same gradient. In Euclidean geometry (the geometry used in standard mathematics and day-to-day physics), parallel lines will never meet at a point, but will share every point along their (infinite) lengths if 1 point is observed to coincide with both.

The parallel postulate, which is a geometric axiom of Euclid's geometry, defines these properties. However, by moving into elliptical and hyperbolic geometries, parallel lines can be allow to intersect at points (where parallel lines are defined as 2 lines having the same gradient), whilst still retaining logically consistent geometrical definitions.

Parallel lines are the opposite of perpendicular lines which meet at right angles.

Answer 2

Parallel lines are coplanar lines that never touch, their minimum distance apart being the same at any point.

For example (below, Imagine if these lines went on for ever)

------------------------------------------------------------------------------

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(Hint: they would never touch)

Lines that are not parallel include lines such as perpendicular look like this

__l__

l (they cross and form four right angles

Answer 3

Parallel lines are lines that are going in the exact same direction. They never intersect, or cross.Here's an example: l l