Symmetry (Rotational).ppt

8/10/2019 Symmetry (Rotational).ppt

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Rotational Symmetry

5

7 2

1


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Rotational Symmetry All 2 dimensional shapes have some rotational symmetry. The degreeof rotational symmetry that an object has is known as its order.

Order 1 Order 2 Order 3 Order 4

For shapes that have order 2 rotational symmetry or higher, a singlecentre of rotation can be located.For shapes that have only order 1 rotational symmetry a centre of

rotation can be found anywhere within it.


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Rotational Symmetry

Order 11

2

Order 2

12

3

Order 312

3 4

Order 4

The order ofrotational symmetrythat an object has isthe number of timesthat it fits on to itself during a full rotationof 360 0 .


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Rotational Symmetry

Order 11

2

Order 2

12

3

Order 3

The order ofrotationalsymmetry thatan object has

is the numberof times that itfits on to itself during a fullrotation of360 0


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What is the order of rotational symmetry of the shape below?

Rotational Symmetry


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1

23

4

5What is the order of rotational symmetry of the shape below?

Order 5

Rotational Symmetry


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Rotational Symmetry


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1

2

3

4

5


Order 6

Rotational Symmetry

6


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Equilateral Triangle

An equilateral triangle has rotational symmetry of order ?


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12

33

This shape has rotational symmetry every 120 degrees.


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Square

A square has rotational symmetry of order ?

Square


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Square



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Square


12

3

4

4

A square has rotational symmetry every 90 degrees.360 4 = 90


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Pentagon

Regular Pentagon

A regular pentagon has rotational symmetry of order ?


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Regular Pentagon

A regular pentagon has rotational symmetry of order ?


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Regular Pentagon

A regular pentagon has rotational symmetry of order ? 5

1

23

4

5

A regular pentagon has rotational symmetry 5 times. 360 degreesdivide by 5 means it matches up every 72 degrees.


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Hexagon

Regular Hexagon

A regular hexagon has rotational symmetry of order ?


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Regular Hexagon

A regular hexagon has rotational symmetry of order ?


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1

23

4

5 6

Regular Hexagon

A regular hexagon has rotational symmetry of order ? 6

The hexagonhas rotationalSymmetry 6

times. 360 6.It has

symmetryeveyy 60

degrees


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Regular Octagon

A regular octagon has rotational symmetry of order ?

Octagon


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1

2

34

5

6

Regular Octagon

A regular octagon has rotational symmetry of order ? 8

7 8 The regularoctagon has 8

points ofrotational

symmetry. Itmatches up

3608 or every45 degrees !


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Rectangle

Rectangle

A rectangle has rotational symmetry of order ?


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2

1

2

Rectangle

A rectangle has rotational symmetry of order ?

This rectangle is not a regular polygon. It will show rotationalsymmetry only twice. 360 degrees2 every 180 degrees


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Parallelogram

Parallelogram

A parallelogram has rotational symmetry of order ?


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2

1

2

Parallelogram

A parallelogram has rotational symmetry of order ?

How many degrees must this parallelogram rotate before it showssymmetry?


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Isosceles Triangle

An isosceles triangle has rotational symmetry of order ?


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11

Isosceles Triangle

An isosceles triangle has rotational symmetry of order ?


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Scalene

Scalene Triangle

An scalene triangle has rotational symmetry of order ?


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1

1

Scalene Triangle

An scalene triangle has rotational symmetry of order ?


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Isos Trapezium

Isosceles Trapezoid

A isocelese trapezoid has rotational symmetry of order ?


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1

1

Isosceles Trapezium

An isosceles trapezioid has rotational symmetry of order ?

Since there is no symmetry until it has rotated the entire 360 degrees,the order of symmetry is one.


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Trapezium

Right Trapezoid

A trapezium has rotational symmetry of order ?


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1

1

A right trapezoid has rotational symmetry of order ?

Right Trapezoid


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A kite has rotational symmetry of order ?

Kite

Kite


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11

A kite has rotational symmetry of order ?

Kite

Kite


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Rhombus

A rhombus has rotational symmetry of order ?

Rhombus


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Ellipse

An ellipse has rotational symmetry of order ?

Ellipse


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Ellipse

2

1

An ellipse has rotational symmetry of order ?

Ellipse

2


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Rotational SymmetryState the order of rotational symmetry for each shape below:

1 2 3 4

5 6 7 8

9 10 11 12


Order 1 Order 3 Order 2Order 5



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13 14 15 16

17 18 19 20

21 22 23 24





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Now..its the time for

To ignite your minds..


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@ First, Observe the given Picture carefully.

@ Try to Imagine the rotation

@ Concentrate on the inner designs also

@ Each question carries 1m as usual

@ Time limit for each Work sheet is 5 min., only

# WRITE ONLY THE ORDER OF ROTATIONALSYMMETRY IN THE GIVEN BOXES


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Worksheet 1


1 2 3 4

5 6 7 8

9 10


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13 14

15 16 17 18

19 20

11 12

Symmetry (Rotational).ppt

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