Which of the following are models for perpendicular lines
(a) The adjacent edges of a tabletop.
(b) The lines of a railway track.
(c) The line segments forming the letter ‘L’.
(d) The letter V.
(a) The adjacent edges of a tabletop = Perpendicular
(b) The lines of a railway track = Not perpendicular as they are parallel.
(c) The line segments forming the letter ‘L’ = Perpendicular. The vertical line and horizontal line makes an angle of 90∘.
(d) The letter V = Not perpendicular as the two lines form an acute angle.
Therefore, options (a) and (c) are models of perpendicular lines.