\(\angle AKO = \angle BKO = \frac{86^{\circ}}{2} = 43^{\circ}\).
\(\angle OAK = 90^{\circ}\).
\(\angle AOK = 180^{\circ} - 90^{\circ} - 43^{\circ} = 47^{\circ}\).
\(\angle AOB = 2 \cdot 47^{\circ} = 94^{\circ}\).
\(\angle OAB = \angle OBA = \frac{180^{\circ} - 94^{\circ}}{2} = \frac{86^{\circ}}{2} = 43^{\circ}\).
Ответ: 43