1. Lines of Symmetry
A figure has line symmetry, or reflectional symmetry, if there is a reflection for which the figure is its own image.

2. Examples of lines of symmetry
NON-examples of lines of symmetry

3. Rotational Symmetry
If you can rotate (or turn) a figure around a center point by fewer than 360° and the figure appears unchanged, then the figure has rotational symmetry.
The point around which you rotate is called the center of rotation.
The smallest angle you need to turn is called the angle of rotation.

4. Rotational Symmetry Examples
This figure has rotational symmetry of 72°, and the center of rotation is the center of the figure:
Other examples of rotational symmetry:

5. Hmmmm…
How can you find the # of lines of symmetries for any regular polygon?
How do you find the angle of rotation of any regular polygon?

6. Reflectional Symmetry
The number of lines of symmetry is equal to the number of sides.

7. Rotational Symmetry Angle of rotation for regular polygons is:
360 𝑛
where n is the number of sides.
360 5 =72° =60°
Ex:

8. What regular polygons have 90° rotational symmetry
What regular polygons have 90° rotational symmetry? Explain your reasoning. .
squares