Cheers tony, the actual storage of the information wasn't the problem (well it isnt yet ;) It's more the working out of the coordinates. Like, I know the red coords, I know the radius of the circle and I would like it to work out the green coords.

So the function would be something like
function roundCorner(x1#, y1#, x2#, y2#, x3#, y3#, radius#, detail:int)
where detail specifies how many coords to return.

So the function would be something like
function roundCorner(x1#, y1#, x2#, y2#, x3#, y3#, radius#, detail:int)
where detail specifies how many coords to return.