Answer:
60°
Step-by-step explanation:
B and C are the points of intersection of the circle with diameter AO with circle O. If the midpoint of AO is X on circle O, then XO = XB = XC and ΔXOB and ΔXOC are equilateral triangles. That makes ∠BOC = 120° and its supplement, ∠BAC, equal to 60°.
