AOB = 360 - 250 = 110 degrees
The subtended angle to the arc is half its measure,
BDA = AOB/2 = 55 degrees
The two tangents at A and B make right angles to the radius so the remaining angles in the quadrilateral OBCA are supplementary.
BCA = 180 - AOB = 180 - 110 = 70 degrees
Answer: BDA = 55° and BCA = 70°
