symmetry

Symmetry is when a shape (or part of a shape) looks the same after it has been moved or reflected or rotated.

A shape is symmetrical if it has two matching sections.

Line symmetry is when a shape can be split into sections with a line and each section looks the same as the other section.

The line is called a mirror line or the axis of symmetry.

A square has 4 mirror lines (or axes of symmetry).

A rectangle only has 2 mirror lines (or axes of symmetry).

Rotational Symmetry is when a shape can rotate 'onto' itself. 

It is the number of times a shape looks exactly the same after one full revolution.

This is called the order of rotational symmetry.

A regular pentagon will rotate onto itself ("look the same") 5 times as it rotates around a full turn. 

It has an order of rotational symmetry of 5.