Transcript Rotational Symmetry

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Rotational
Symmetry
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Rotational Symmetry
• If, when you rotate a shape, it looks exactly
the same as it did in its original position, then
we say that the shape has got rotational
symmetry.
• This square has got rotational symmetry.
• It looks exactly the same four times in a full turn.
• It has got rotational symmetry order 4.
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Rotational Symmetry
• Does this rectangle have rotational symmetry?
No,Yes,
it doesn’t
it fits! fit
Click to rotate the rectangle.
• It looks exactly the same twice in a full turn.
• It has got rotational symmetry order 2.
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Rotational Symmetry in the Alphabet
Which letters have got rotational symmetry?
Click to see the answers.
A B C D E F G H I
J K L M N O P Q R
S T U V W X Y Z
Order 2
Order 2
Order 2
Order 2
Order 2
Order 2
Order 2
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Rotational Symmetry all around us
Which road signs have got rotational symmetry?
Click to see the answers.
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Rotational Symmetry all around us
Click to see the road signs with rotational symmetry.
Order 3
Order 2
Order 2
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Rotational Symmetry all around us
Click to see more road signs with rotational symmetry.
Order 4
Order 3
Order 2
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Rotational Symmetry all around us
Click to see more road signs with rotational symmetry.
Order 3
Order 2
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Rotational Symmetry with
Pentominoes
• If you don’t know what a pentomino is, then
click here.
• If you have done the pentominoes activity
before, then you will know what a pentomino
is and how many different pentominoes there
are.
• Here they are ...
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Rotational Symmetry with
Pentominoes
Which Pentominoes have got rotational symmetry?
Sort them according to their rotational symmetry.
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Rotational Symmetry with Pentominoes
Rotational Symmetry Order 2
Rotational Symmetry Order 4
Click to start sorting
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Rotational Symmetry with 7-Pin
Polygons
• If you don’t know what a 7-pin polygon is,
then click here.
• If you have done the 7-pin polygons activity
before, then you will know what a 7-pin
polygon is and how many different ones there
are.
• Here they are ...
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Rotational Symmetry with 7-Pin
Polygons
Which 7-Pin Polygons have got rotational symmetry?
Sort them according to their rotational symmetry.
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Rotational Symmetry with 7-Pin Polygons
Rotational Symmetry
Order 2
Rotational Symmetry
Order 3
Click to start sorting
Rotational Symmetry
Order 6
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Now you know all about rotational
symmetry!
END OF PRESENTATION
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Pentominoes
A pentomino is made out of five squares that are
connected along at least one edge.
Here is an example
of a pentomino.
These are NOT
pentominoes.
How many different pentominoes can you find?
Click here to return to line symmetry.
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7-Pin Polygons
Here is an arrangement of 7 pins.
A 7-pin polygon is a closed shape with
straight sides with corners on the pins.
Here are some examples of 7-pin polygons.
How many different 7-pin polygons can you find?
Click here to return to line symmetry.
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END OF PRESENTATION