__CHAPTER 13 SYMMETRY__LINE SYMMETRY

A figure has a line symmetry if there is a line about which the figure may be folded so that the two parts of the figure will coincide.

Number of lines of symmetry of:

1. Regular hexagon= 6

2. Regular pentagon= 5

3. Square= 4

4. Equilateral triangle= 3

The fixed point about which a figure is rotated is called its centre of rotation.

The angle by which the object is rotated is called the angle of rotation.

After rotation, if the object looks exactly the same, it is said to have rotational symmetry.

In a complete 3600 turn, the number of times an object looks exactly the same is called the order of rotational symmetry.