Area of a circle inscribe a hexagon. Cut the hexagon into six triangles by splitting it from the center. Two opposite triangles both touch two common diameters; slide them along one so the radial edges are adjacent. They now form a parallelogram, with the hexagon sides making two opposite edges, one of which is the base, "s". Two radial edges form slanted sides, and the height, "h" is equal to its apothem (as in the Archimedes proof). In fact, we can assemble all the triangles into one big parallelogram by putting successive pairs next to each other. The same is true if we increase
Rebate plane Rebate plane The rebate plane (also known as the rabbet plane) is a hand plane designed for cutting rabbets in wood. It's a simple tool used in many Western countries with hundreds of years of history. It was in use in England at least as early as the 11th century. The rebate plane is one of a group of planes, including the shoulder plane, bullnose plane and carriage makers plane, in which the blade protrudes by a very small amount - usually less than half a millimetre - from the sides of the plane body on both sides. The blade