Line and Rotational Symmetry

A figure has line symmetry if it can be folded or reflected so that the two parts of the figure match

Even if two figures are congruent, they may not be symmetrical. They will be symmetrical only if the two parts of the figure match after being folded or reflected

The line of reflection is called the line of symmetry

Irregular figures do not have a line of symmetry

All figures, when rotated by 360° (or a full turn), will look exactly the same as they did before being turned

Some figures will look the same at certain angles of rotation which are less than 360° (90°, 180°, 270°). Such figures have rotational symmetry
For example, the figure of a square reappears in the same position as it is turned 90°, 180°, 270° and 360°

The degree measure of the angle through which the figure is rotated is called the angle of rotation. Some figures have just one angle of rotation, while others, have several

A figure that coincides with itself n times within a full circle has n-fold rotational symmetry

If a figure has line symmetry then,
Angle of rotation = 360°/Number of lines of symmetry