Prove that the tangents drawn at the end points of a chord of a circle make equal angles with the chord

Prove that the tangents drawn at the end points of a chord of a circle make equal angles with the chord.

Case I:

Since PA = PB

Therefore in ΔPAB

∠PAB= ∠PBA

Case II:

If the tangents at A and B are parallel then each angle between chord and tangent = 90°