Answer:
∠ BAF = 140°
Explanation:
Since BD is a tangent to the circle at point B , then
∠ ABD = 90°
The exterior angle of a circle is equal to the sum of the 2 opposite interior angles.
∠ BAF is an exterior angle, thus
∠ BAF = ∠ ABD + ∠ BDA = 90° + 50° = 140°