Contents• Slide Slide no.• What is Symmetry? 3• Symmetry 4• Common Errors 5• Letters & Line Symmetry 6• Letters & Rotational Symmetry 7• Nature & Line Symmetry 8• Road Signs & Symmetry 9• Monuments & Symmetry 10• Flags & Line symmetry 11• Flags & Rotational Symmetry 12• Math Symbols & Symmetry 13• Tattoos & Line Symmetry 14• Religious Symbols & Symmetry 15• Words & Rotational Symmetry 16• Objects & Symmetry 17• Line Symmetry 18• Revision of What we have done 19• The End 20

• An image has Rotational Symmetry if there is a center point An image has Rotational Symmetry if there is a center point around which the object is turned a certain number of degrees around which the object is turned a certain number of degrees and the object still looks the same.and the object still looks the same.

an equilateral triangle has 3 internal angles,3 lines of symmetry & a rotational symmetry at order 3. 

a square has 4 internal angles, 4 lines of symmetry & a rotational symmetry at order 4. 

a regular pentagon has 5 internal angles,5 lines of symmetry & a rotational symmetry at order 5. 

a regular hexagon has 6 internal angles,6 lines of symmetry & a rotational symmetry at order 6. 

a regular octagon has 8 internal angles,8 lines of symmetry & a rotational symmetry at order 8.  A shape has line symmetry when one half of it is the A shape has line symmetry when one half of it is the

mirror image of the other half.mirror image of the other half.

What is Symmetry ?

Symmetry

Order of Rotation24Lines of symmetry 21

• There are some examples of shapes that are tricky when considering symmetry. A typical parallelogram actually cannot be folded in half even though it appears to have two 'equal halves'.

• We can see both kinds of symmetry around us; rotational as well as line symmetry.

• Lets see some of the interesting topics related to symmetry.

Common Errors

Letters and Line Symmetry.

A B C D E

F G J K L N P Q S Z

H I M OT U V W X YThere are some letters

which do not have any line of symmetry.

H

N

SX

I

O

Z

rotational symmetry at order 1

rotational

symmetry at

order 2rotational symmetry at order 2

rotational symmetry at order 2

rotational symmetry at order 2

rotational symmetry at order 2

rotational symmetry at order 1

Letters and Rotational Symmetry.

• This flower has 1 line of symmetry and a rotational symmetry of Order 5 as it matches itself 5 times.

Nature & Line Symmetry.

Order 4+4 lines of symmetry

Order 3+0 line of symmetry.

Order 2+0 line of symmetry.

Order 3+0 lines of symmetry. Order 2+1 line of symmetry.

Order 1+1 line of symmetry.

Road Signs & Symmetry.

Monuments & Symmetry.Symmetry exists in architecture all around the world. One of the best known examples of this is the Taj Mahal.

If an object is reflected in water many people believethe image has line symmetry. But is it really a 'mirror image'? Is it really symmetrical? What are your thoughts? The image can be rotational symmetry.

Indonesia Japan

Finland

Micronesia Aboriginal Flag of AustraliaUnited Nations

British Canada

Flags & Line Symmetry.

Flags and Rotational Symmetry.Rotational symmetry-

yes(2)

Rotational symmetry-yes(2)

Rotational symmetry-yes(1)

Rotational symmetry-yes(1)

Rotational symmetry-yes(2)

Rotational symmetry-yes(1)

Rotational symmetry-yes(1)

Rotational symmetry-yes(1)

Math symbols & Symmetry.

Masks,tattoos &

Symmetry.

The Memorah is used during the Jewish feast of Chanukah.

The Dharma Wheel is a Buddhist  symbol. 

Muslim buildings often have symmetry.

The Jewish Star of David.The Christian Cross

L.S-1 

R.S-0

L.S-4

R.S-0L.S-1

R.S-8

L.S-6 R.S-6

L.S-1 R.S-0

Religious Symbols & Symmetry.

L.S-Line of SymmetryR.S-Rotational Symmetry

Words & rotational symmetry.

Objects & Rotational Symmetry. Order 5• Often the picture cards in a

playing deck have rotational symmetry.

• Since all the toppings are placed so evenly, this pizzahas rotational symmetry of Order 6.

Order 7

Order 2

Click on the shapes to see how many lines of symmetry they have.

Revision of what we just did. • Objects with either line symmetry

or rotational symmetry or both.

Kenya

Brazil

R.L+R

R. R+L

R+L

R+L

R+L

R+LR+L

R

R+L