Quote - The third point can be any point on the curve.

You have to be given that third point or else your back to an iterative process starting with some initial guess.
The length is known because you decide before hand how long a chain you want otherwise you're adding yet another unknown to the mix.

Quote - why isnt this wrapping the text ? bugger

Table cells are always as wide as the longest link
(Actually text in [code] or

 tags doesn't wrap)