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13 Symmetry
The concept of symmetry is fundamental in the study of geometry,
nature and art. When one half of an object is a mirror image of
the other, the object is said to have line symmetry. Look at the
picture of Taj Mahal. Its symmetry adds to its beauty.
Line of Symmetry
On looking at the following pictures or figures, we observe
that if we fold each figure or picture along the respective dotted line(s) shown, the two parts of
the figure will superimpose on each other.
If a figure is divided into two identical halves by a line drawn through it or if the figure is folded
along a line and the two parts on either side of the line coincide with each other, then the figure
is said to have line symmetry and the line is called the axis of symmetry or simply the line of
symmetry. Therefore, we conclude that all these figures are symmetrical and the dotted lines are
the ‘lines of symmetry’. Can you identify more lines of symmetry in the above figures?
• The line of symmetry divides the figure into two halves which are also mirror images of each other. It is
also called the mirror line.
• A figure may have no line of symmetry, or it may have one or more lines of symmetry.
