Symmetry

A shape has symmetry when one half is a mirror image of the other. The imaginary fold line is called the line of symmetry (or mirror line).

To check for symmetry, imagine folding the shape along the line. If both halves line up perfectly, the line is a line of symmetry. A rectangle has 2 lines of symmetry, while a regular hexagon has 6.

A regular shape (where all sides are the same length) has the same number of lines of symmetry as it has sides. A regular triangle has 3, a square has 4, a regular pentagon has 5, and a regular hexagon has 6. That is a very neat pattern!

To draw the mirror image of a shape on squared paper, count how many squares each point is away from the mirror line, then draw the same point the same distance on the other side. A point 2 squares to the left of the line maps to a point 2 squares to the right.

Some capital letters are symmetrical and some are not. A, H, I, M, O, T, U, V, W, X and Y have at least one line of symmetry. Letters like F, G, J, L, P, Q and R have none — you cannot fold them so the halves match.