1. Describing Rotations

3. Rotational Symmetry in Nature

4. Rotational Symmetry in the world…

5. Rotation Symmetry The compass star has rotation symmetry.
You can turn it around its center point to a position in which it looks identical to the original figure.

6. Rotation Symmetry
How many degrees will I need to rotate point A so it will line up on point C?
90˚ clockwise
How many degrees will I need to rotate point A so it will line up on point E?
180˚ clockwise

7. Rotation Symmetry
How many degrees will I need to rotate point A so it will line up on point G?
270˚ clockwise
How many degrees will I need to rotate point A so it will line up on point A?
360˚ clockwise

8. Rotational Symmetry Rules
A shape has rotational symmetry if it fits onto itself two or more times in one complete turn.
First, determine how many times a figure can land on itself including the full turn.
Then divide 360˚ by that number to get the first rotational degree.
For example, the figure above can be turned and land on itself 4 times.
360˚ ÷ 4 = 90˚.
The rotational degrees are 90˚, 180˚, 270˚ and 360˚.

9. Determine if the shape has rotational symmetry
Determine if the shape has rotational symmetry. If it does, find all of its rotational symmetries.
Yes = 180˚, 360˚

10. Determine if the shape has rotational symmetry
Determine if the shape has rotational symmetry. If it does, find all of its rotational symmetries.
Yes = 120˚, 240˚ & 360˚

11. Determine if the shape has rotational symmetry
Determine if the shape has rotational symmetry. If it does, find all of its rotational symmetries.
No rotational symmetry

12. Determine if the shape has rotational symmetry
Determine if the shape has rotational symmetry. If it does, find all of its rotational symmetries.
Yes = 60˚, 120˚, 180˚, 240˚ 300˚, & 360˚