Triangle knowing the vertex A, the circumcenter O and the symmedian point K

1) Let L be the midpoint between O and K.
2) Let M be the midpoint between A and K.
3) Draw the perpendicular from M to LM.
4) Place a segment NP on this line, with midpoint M and length .
5) AN and AP cut the circle with center O through A at the vertices B and C.
An alternative construction is c26.