Question

which of the following best completes this definition? two lines are parallel if and only if _. a. they intersect and form acute angles b. they do not lie in the same plane and do not intersect c. they intersect and form right angles d. they lie in the same plane and do not intersect

Explanation:

Parallel lines are defined as lines that are in the same plane and never intersect. Option A describes intersecting lines forming acute - angles, which are not parallel. Option B describes skew lines (lines not in the same plane and not intersecting), not parallel lines. Option C describes perpendicular lines (intersecting at right - angles), not parallel lines.

Answer:

D. they lie in the same plane and do not intersect