1. Symmetry

2. We find it in architecture…
…on a large scale…

3. …and on an every day scale

4. We find it in nature…

5. We find it in ancient things…

6. We find it in art…

7. We find it in optical illusions…

8. So…how can we define symmetry?
Symmetry is all around us
If an object can be balanced, or can fit into itself by reflection, rotation or translation – it has symmetry
An object can have
line symmetry, or
rotational symmetry
Symmetry is related to motion geometry in that the object can be moved

9. Line symmetry
Line symmetry occurs where an object can be divided into two reflected parts.
This line is sometimes called a line of reflection or an axis of symmetry
The line can be vertical, horizontal or oblique (slanted)
An object can have one or more lines of symmetry – or none.

10. Examples of line symmetry

11. More examples of line symmetry
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12. Time to practice! Complete the “Investigate sheet”
Complete the sheet entitled “Creating lines of symmetry”.

13. Rotation symmetry

14. Rotation symmetry