Page 249 - Ganit Kaushal

4. Shapes with more than two lines of symmetry:

Equilateral triangle Square Pentagon Hexagon Circle
(3-lines of symmetry) (4-lines of symmetry) (5-lines of symmetry) (6-lines of symmetry) (Infinite-lines of symmetry)

Solved Examples

Ex 1. Find the number of lines of symmetry for each of the following shapes: (NCERT)

(a) (b) (c)

Sol. Dotted lines show the lines of symmetry.

(a) (b) (c)

6 lines of symmetry 6 lines of symmetry 4 lines of symmetry
Ex 2. In each of the following figures, a square sheet of paper was folded along a line of symmetry. A hole
was punched in the folded paper, and then the paper was unfolded. Identify the line of symmetry along
which the paper was folded. Figure (d) was created by punching a single hole. How was the paper
folded? (NCERT)

(a) (b) (c) (d)

Sol. The lines of symmetry are shown by the black dotted lines.

(a) (b) (c) (d)

In figure (d), the paper was folded twice – first, along the horizontal line of symmetry, and then along

the vertical line of symmetry. Then, a single punch hole would create 4 holes, as shown in the above
figure.

Symmetry 247