Hexagon of the circumscribed circle, which equals formula_1 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 D. 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
A Plane Is Born training at Staverton Airport in Gloucestershire with instructor Carl Bowen. - Building Begins Mark learns that before he starts to build his aeroplane he must attend a workshop on composite building techniques. His crash course is instructed by expert Neville Eyre. In part 2, back at the workshop, he begins work on his kit plane, starting with the Rudder. Some respite from plastics is provided at Gloucester airport where his flying training continues apace. In a regular feature, Dudley Pattison shows us the Isaac's Fury biplane he took fifteen years to build. - Wings Filming in the workshop, work begins