Rotational SymmetryRotational Symmetry

5

7 21

Rotational SymmetryAll 2 dimensional shapes have some rotational symmetry. The degree of 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 single centre of rotation can be located.

For shapes that have only “order 1” rotational symmetry a centre of rotation can be found anywhere within it.

Rotational Symmetry

Order 11

2

Order 2

12

3

Order 312

3 4

Order 4

The order of rotational symmetry that an object has is the number of times that it fits on to itself during a full rotation of 3600 .

Rotational Symmetry

Order 11

2

Order 2

12

3

Order 3

The order of rotational symmetry that an object has is the number of times that it fits on to itself during a full rotation of 3600

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

Rotational Symmetry

1

23

4

5

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

Order 5

Rotational Symmetry

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

Rotational Symmetry

1

2

3

4

5

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

Order 6

Rotational Symmetry

6

Equilateral Triangle

An equilateral triangle has rotational symmetry of order ?

Equilateral Triangle

An equilateral triangle has rotational symmetry of order ?

Equilateral Triangle

An equilateral triangle has rotational symmetry of order ?

12

33

This shape has rotational symmetry every 120 degrees.

Square

A square has rotational symmetry of order ?

Square

Square

A square has rotational symmetry of order ?

Square

A square has rotational symmetry of order ?

12

3

4

4

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

Pentagon

Regular Pentagon

A regular pentagon has rotational symmetry of order ?

Regular Pentagon

A regular pentagon has rotational symmetry of order ?

Regular Pentagon

A regular pentagon has rotational symmetry of order ? 5

1

23

4

5

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

Hexagon

Regular HexagonA regular hexagon has rotational symmetry of order ?

Regular HexagonA regular hexagon has rotational symmetry of order ?

1

23

4

5 6

Regular HexagonA regular hexagon has rotational symmetry of order ? 6

The hexagon has rotational

Symmetry 6 times. 360 ÷6.

It has symmetry eveyy 60 degrees

Regular OctagonA regular octagon has rotational symmetry of order ?

Octagon

1

2

34

5

6

Regular OctagonA regular octagon has rotational symmetry of order ? 8

7 8 The regular octagon has 8

points of rotational

symmetry. It matches up

360÷8 or every 45 degrees !

Rectangle

RectangleA rectangle has rotational symmetry of order ?

2

1

2

RectangleA rectangle has rotational symmetry of order ?

This rectangle is not a regular polygon. It will show rotational symmetry only twice. 360 degrees÷2 every 180 degrees

Parallelogram

ParallelogramA parallelogram has rotational symmetry of order ?

2

1

2

ParallelogramA parallelogram has rotational symmetry of order ?

How many degrees must this parallelogram rotate before it shows symmetry?

Isosceles TriangleAn isosceles triangle has rotational symmetry of order ?

1

1

Isosceles TriangleAn isosceles triangle has rotational symmetry of order ?

Scalene

Scalene TriangleAn scalene triangle has rotational symmetry of order ?

1

1

Scalene TriangleAn scalene triangle has rotational symmetry of order ?

Isos Trapezium

Isosceles TrapezoidA isocelese trapezoid has rotational symmetry of order ?

1

1

Isosceles TrapeziumAn 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.

Trapezium

Right TrapezoidA trapezium has rotational symmetry of order ?

1

1

A right trapezoid has rotational symmetry of order ?

Right Trapezoid

A kite has rotational symmetry of order ?

Kite

Kite

1

1

A kite has rotational symmetry of order ?

Kite

Kite

Rhombus

A rhombus has rotational symmetry of order ?

Rhombus

2

1

A rhombus has rotational symmetry of order ?

Rhombus

2

Ellipse

An ellipse has rotational symmetry of order ?

Ellipse

Ellipse

2

1

An ellipse has rotational symmetry of order ?

Ellipse

2

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

1 2 3 4

5 6 7 8

9 10 11 12

Order 6 Order 2 Order 3 Order 2

Order 1 Order 3 Order 2 Order 5

Order 4 Order 1 Order 6 Order 8

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

13 14 15 16

17 18 19 20

21 22 23 24

Order 4 Order 1 Order 2 Order 5

Order 2 Order 4 Order 6 Order 3

Order 5 Order 4 Order 3 Order 1

Now..it’s the time for…Now..it’s the time for…

To ignite your minds..To ignite your minds..To ignite your minds..To ignite your minds..

@ 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 ROTATIONAL SYMMETRY IN THE GIVEN BOXES

Worksheet 1

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

1 2 3 4

5 6 7 8

9 10

Worksheet 2

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

13 14

15 16 17 18

19 20

11 12