Half of each figure exactly coincides with the other half. Such figures are symmetrical about that line and that line is called the line of symmetry or the axis of symmetry.

**Line
of Symmetry**

In the given figures, the red coloured line divides
each figure into two equal halves and suppose we fold them along that line, we will
see that one half of each figure exactly coincides with the other half. Such
figures are symmetrical about that line and that line is called *the line
of symmetry or the axis of symmetry.*

Look at the given invitation cards, the fold line of the first card divides it into two equal
halves and each half exactly coincides. Hence it
is a line of symmetry but in the second card, the fold line does not divide it into two equal halves. So, it is not a line of symmetry.

A figure may have one, two, three or more lines of symmetry or no line of symmetry.

** **

**Think**

The diagonal of a rectangle divides it
into two equal halves but it is not a line of symmetry. Why?

**Note**

The line of symmetry can be vertical,
horizontal or slant.

The word
“symmetry” comes from the Greek word “symmetros” which means “having a common measure”.

** **

**Some examples for Symmetry**

Symmetry can be found anywhere in nature as well
as in man-made objects. A few of them are leaves, insects, flowers, animals, note
books, bottles, architecture, designs and shapes, etc.,

We observe a few symmetrical things in our surroundings
as follows.

**Symmetry in Kolams**

In Tamilnadu, our people usually decorate their
corridors by beautiful *kolams* using rice
flour. Those *kolams* look beautiful as
most of them are symmetrical.

** **

**Try these**

1. Is the dotted line shown in each
figure a line of symmetry? If yes put **✓** otherwise
put **×**. Justify
your answer.

2. Check the following figures for
symmetry? Write **YES** or **NO**.

** **

__Example 1__

Draw the lines of symmetry for the given figures
and also find the number of lines of symmetry.

** Solution:**

** **

__Example 2 __

Draw the lines of symmetry for each
of the letters in the word**
****RHOMBUS**** **and also find the number of lines of
symmetry. (**Note:** Here the letter ‘O’ is in circle shape.)

*Solution:*

** **

__Example 3 __

Draw the lines of symmetry for an equilateral
triangle, a square, a regular** **pentagon
and a regular hexagon and also find the number of lines of symmetry.

*Solution:*

** **

**Note**

The number of lines of symmetry of
each regular polygon (a closed figure having equal sides and equal angles) is equal
to its number of sides.

** **

**Try these**

**1. Draw the following figures in a paper. Cut out each of them and
fold so that the two parts of each figure exactly coincide.**

**i) Which of the above figures have
one, two or more lines of symmetry?**

1 st, 3rd, 4th and 5th
figures.

**ii) Which of the above figures do
not have any line of symmetry?**

Parallelogram

**2. Write the numbers from 0 to 9.**

0, 1, 2, 3, 4, 5, 6, 7, 8,
9.

**i) Which numbers have a line of symmetry?**

0, 1, 3, 8.

**ii) List out the numbers which do not have a line of symmetry.**

2, 4, 5, 6, 7, 9.

__Example 4 __

Complete the other half of the following figures
such that the dotted line is a line of symmetry.

*Solution*

** **

**Activity**

Complete the other half of the following
figures such that the dotted line is the line of symmetry.

Tags : Symmetry | Term 3 Chapter 4 | 6th Maths , 6th Maths : Term 3 Unit 4 : Symmetry

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6th Maths : Term 3 Unit 4 : Symmetry : Line of Symmetry | Symmetry | Term 3 Chapter 4 | 6th Maths

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