Another kind of symmetry?

1
Another kind of symmetry?
Centre of rotation

• What might we call this kind of symmetry?

Rotational Symmetry
2
We say a shape has rotational symmetry if it fits
exactly into itself when it is rotated.

• How many times does this shape fit into itself?

We say it has rotational symmetry of order 4
3
What happens if we move the centre of rotation?
Centre of rotation

• Do we still have rotational symmetry?

Do we now have rotational symmetry?
Yes
No
4
Does this shape have rotational symmetry?

• What is the order of rotation?

2
We call this half turn symmetry.
5
Creating shapes with rotational symmetry

• We want this shape to have rotational symmetry
  order 2

6
Creating shapes with rotational symmetry
We want this shape to have rotational symmetry of
order 4.
We say this shape has quarter turn symmetry.