how many lines of symmetry does hexagon have
Hexagon The common length of the sides equals the radius of the circumscribed circle, which equals    2 3    {\displaystyle {\tfrac {2}{\sqrt {3}}}}  times the apothem (radius of the inscribed circle). All internal angles are 120 degrees. A regular hexagon has 6 rotational symmetries (rotational symmetry of order six) and 6 reflection symmetries (six lines of symmetry), making up the dihedral group D6. The longest diagonals of a regular hexagon, connecting diametrically opposite vertices, are twice the length of one side. From this it can be seen that a triangle with a vertex at the center of the regular hexagon and sharing one side with the hexagon is equilateral, and that the regular hexagon can be partitioned into six equilateral triangles.
Symmetry in biology Symmetry has been important historically in the taxonomy of animals; Georges Cuvier classified animals with radial symmetry in the taxon Radiata (Zoophytes),[1][2] which is now generally accepted to be a polyphyletic assemblage of different phyla of the Animal kingdom.[3] Most radially symmetric animals are symmetrical about an axis extending from the center of the oral surface, which contains the mouth, to the center of the opposite, aboral, end. Radial symmetry is especially suitable for sessile animals such as the sea anemone, floating animals such as jellyfish, and slow moving organisms such as starfish. Animals in the phyla Cnidaria and Echinodermata are radially symmetric,[4] although many sea anemones and some corals have bilateral symmetry defined by a single structure, the siphonoglyph.[5]