NCERT Exemplar Solutions
Class 6 - Mathematics - Unit 9: Symmetry and Practical Geometry - Multiple Choice Questions
Question 13

Question.  13

The number of lines of symmetry in compasses is

(A)

0

(B)

1

(C)

2

(D)

3

Detailed Answer with Explanation:

Explanation (Very Beginner Friendly)

Correct Option: A (0)

Key Idea

A line of symmetry is a line that splits a shape into two exact mirror halves. If you fold the shape along this line, both parts match perfectly.

Understand the Object

  • A compass (used for drawing circles) has two legs.
  • One leg holds a pencil.
  • The other leg has a metal point (needle).
  • So, the two sides are not the same.

Step-by-Step Check for Symmetry

  1. Try a vertical line through the middle.
    Left side (pencil) ≠ Right side (needle). They don’t match.
    No vertical line of symmetry.
  2. Try a horizontal line through the middle.
    Top part ≠ Bottom part (shape and parts are different).
    No horizontal line of symmetry.
  3. Try a slanted line (any angle).
    Because the legs and their ends (pencil vs needle) are different, folding along any slanted line also won’t match.
    No slanted line of symmetry.

Why Options B, C, D are Wrong

  • 1 line (B): would need both sides to be the same across that line — they are not.
  • 2 lines (C): needs even more sameness — not possible here.
  • 3 lines (D): only very regular shapes (like an equilateral triangle has 3) have this — a compass is not one.

Conclusion

Since the two legs are dissimilar (pencil vs needle), the compass has no line of symmetry.

Common Mistake

Do not confuse the compass with a V-shape having equal sides. Even if the angle looks similar, the ends are different, so it is not symmetric.

NCERT Exemplar Solutions Class 6 – Mathematics – Unit 9: Symmetry and Practical Geometry – Multiple Choice Questions | Detailed Answers