Of course there are infinitely many solutions, but I beware of that before the wind blow !

That is, I drew on the sand any triangle, and placed a black stone anywhere on each side [or extensions].

I also drew the circumcircle and put three white stones anywhere on it.

The next day, the wind has blown away my drawing, leaving just the stones.

Find back the triangle I had drawn.

Hint

Details

Note : this is the problem of Cramer-Castillon :

To construct a triangle inscribed in a circle, and whose sides go through three given points.