AP is tangent to the circle at A. Therefore OA and AP are perpendicular to each other.

Therefore, \( \Large \angle OAP = 90 ^{\circ} \)

Again \( \Large OA\ =\ OB \)

Therefore, \( \Large \angle OAB = \angle OBA = 42 ^{\circ} \)

Therefore, \( \Large \angle PAB= \angle PAO - \angle BAO \)

= \( \Large 90 ^{\circ} - 42 ^{\circ} = 48 ^{\circ} \)