You've got a which is the radius of the circle, and b which is the length of the arc, thus you've got the angle between the two red radiuses : u = b / a So with basic trigonometry, we can deduce a - x = a * cos(u/2) x = a *( cos(u/2) - 1)
-- Jedaï _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
