Hexagon circle) with vertices given by the six intersections of the edges of a triangle and the three lines that are parallel to the edges that pass through its symmedian point. If the successive sides of a cyclic hexagon are "a", "b", "c", "d", "e", "f", then the three main diagonals intersect in a single point if and only if . If, for each side of a cyclic hexagon, the adjacent sides are extended to their intersection, forming a triangle exterior to the given side, then the segments connecting the circumcenters of opposite triangles are concurrent. If a hexagon has vertices
Shoulder plane for joinery. Unlike the rebate plane, the shoulder plane is intended to cut end grain. There are therefore differences between it and a rebate plane in the angles at which the iron (blade) is set. A shoulder plane also has a much finer set mouth, which allows finer shavings to be taken. Shoulder plane The shoulder plane (also bullnose plane) is a plane tool with a blade flush with the edges of the plane, allowing trimming right up to the edge of a workpiece. Like a rebate plane, the shoulder plane's blade extends, therefore cuts, to the full width of