Question

What are non-parallel and non-intersecting lines called?

(a) Spiral lines

(b) Parallel lines

(c) Skew lines

(d) Perpendicular lines

The question was posed to me in an online quiz.

My query is from Projections on Auxiliary Planes in division Orthographic Projection, Projections of Lines, Planes and Solids of Civil Engineering Drawing

Answer 1

The correct option is (c) Skew lines

The explanation: A simple example of a pair of skew lines is the pair of lines through opposite edges of a regular tetrahedron. Two lines that both lie in the same plane must either cross each other or be parallel, so skew lines can exist only in three or more dimensions. Two lines are skew if and only if they are not coplanar. Referring the figure below, here the line through segment AD and the line through segment B1B are skew lines because they are not in the same plane.