Page 124 - ICSE Math 4

Symmetry

Look at the picture of the bu erfly given alongside carefully.

We can observe that the le side of the bu erfly is similar to its right
side. So we can divide the picture of bu erfly into two similar halves

by drawing a line through the centre of the picture as shown.
Anything which can be divided in such a way that the two parts look exactly similar is called
symmetrical and the line which divides it into similar parts is called the line of symmetry.
Thus, the property of being made of exactly similar parts is known as symmetry.

A fi gure can have one line of symmetry or more than one line of symmetry. The lines of
symmetry can be horizontal, ver cal or both.

Look at the given examples to understand line of symmetry.

Top Tip

The line of symmetry
can be drawn in any
direction.

Horizontal line Ver cal line Horizontal and ver cal
of symmetry of symmetry lines of symmetry
Some fi gures cannot be divided into halves and thus, are not symmetrical.

Mental Maths

Write the letters of the
alphabet which have
no line of symmetry.
Figures with no symmetry

Now, let’s learn about reflec on symmetry.

Refl ection Symmetry Mirror

Reflec on symmetry is a type of symmetry in which
one half of the object is the mirror image or refl ec on
of the other. It is also known as mirror symmetry. For
example, if we stand in front of a mirror and look at
Object Reflec on
it, we will see our image in it. This is our mirror image (Flipped image)
or reflec on.

Reflec ons are seen in many things like mirrors, glass, Remember
water bodies, etc. But the image in the reflec on is The size of an object
always flipped around. and its reflection is
always the same.

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