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NCERT Solutions Ganita Prakash (Part 1) Chapter 5 In-text Questions — Between Lines

Book page 110 Updated on2026-09-05

Q1.
Name some parallel lines you can spot in your classroom.
Answer

Parallel lines are everywhere in a classroom:

  • The top and bottom edges of the blackboard, and its left and right edges.
  • The ruled lines in your notebook.
  • The two long edges of your scale (ruler).
  • The opposite edges of a window pane, of the door, and of a floor tile.
  • The legs of the benches in a row, and the two rails of the ceiling fan's rod holder.
  • The grooves of the roof sheets or the lines of bricks in a wall.
Why it happens: All these pairs lie on the same flat surface and keep the same distance apart along their whole length, so they can never meet.
Tip: The edge of the board and a line drawn on the floor never meet either — but they are not parallel, because they do not lie in the same plane.
Q2.
Which pairs of lines appear to be parallel in Fig. 5.6 below?
Answer

Group the segments by the direction in which they point.

DirectionSegments that are parallel
Vertical (straight up and down)a, i and h
Horizontal (straight across)c and g
Slanting down to the right (45°)d and f
Slanting down to the left (45°)e and b

So the parallel sets are a, i, h; c and g; d and f; e and b.

Why it happens: On dot paper you can read the direction of a segment as "so many dots across, so many dots up". Two segments with the same across-and-up step point the same way, so they are parallel even though they have different lengths and start at different dots.
Check it yourself: Count the steps for d and for f. Both go 1 dot right and 1 dot down for every step — same direction, hence parallel.
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