Page 133 - Maths Skill - 6

Symmetry 131

9. Construct a line segment PQ = 7 cm. Draw its line of symmetry.

10. Find the line/lines of symmetry of the following letters.

, , ,

REFLECTION AND SYMMETRY

Reflection and symmetry both are related to each other. On folding a square paper, the middle line obtained is the
line of symmetry. Similarly, place an object in the front of mirror, the image formed is the reflection of that object
in the mirror.

The dimensions of object and image is always same in plane mirror. During reflection
or when an object is reflected there is not change between length and angles of object
with respect to image. Linear symmetry and reflection symmetry are linked to each
other. Mirror image is same as symmetry except for the fact that the left and right
changes in orientation. Find other letters having reflection symmetry. Fig.

Activity

Take a small mirror and place a figure of DABC in front of it as
shown in given figure.

Now, observe the figure carefully and write your observations:

1. Is DABC and its image symmetrical with reference to the mirror line? ________
2. Is the mirror line, a line of symmetry? ________
3. Is there any change in shape or length of any side of DABC after reflection? ________
4. Can you find any difference between the figure and its mirror image? ________

So, we conclude that when an object is reflected:
● There is no change in the measurement.
● There is no change in the angle.
● The image is as far behind the mirror as the object is in front of the mirror.
● The left side of the object appears on the right side in its mirror image and vice versa.

REAL LIFE APPLICATIONS OF REFLECTION SYMMETRY
Symmetry has a lot of applications in day-to-day life. Some of the examples are:

1. Taj Mahal 2. Art/Rangoli 3. Textile technology 4. Design creations