I don't really understand your algo.lobow wrote:the result x' and y' will be the valors of C.

is it right?

I interpret your steps this way:

Assume we want to build an equilateral triangle ABC. Now, we only know two points (A and B) and going to find the third one (point C).

Let's take an example:

the coordinate of A (0,0) and B (6,0), so the midpoint of AB is (3,0). Using your step we will get C (3,-3), and I think it's not an equilateral triangle.

Maybe if I don't misunderstand yours, you should use it in another way.