Shapes, Symmetry & Tesselation

Symmetry

If a shape has a line of symmetry, the line of symmetry will divide the shape into two equal parts, one half of which can be folded along the line of symmetry to fit exactly onto the other. Note, a rectangle has two (not four) lines of symmetry and a circle has an infinite number.

If rotating a shape through a certain angle produces an identical shape, it has rotational symmetry. If the shape can be rotated 4 times before returning to its original shape (e.g. a square), it has "rotational symmetry of order 4". An equilateral triangle has rotational symmetry of order 3 and a rectangle has rotational symmetry of order 2.

Triangles

Isosceles triangles have two equal angles. The sides ...