

Given, PA and PB from a point P to a circle with center O are inclined to each other at an angle of 80°
Since tangents to a circle is always perpendicular to its radius,
So, ∠OAP = ∠OBP = 90
Now, in quadrilateral OABP,
∠OAP + ∠APB + ∠PBO + ∠BOA = 360
=> 90 + 90 + 80 + ∠BOA = 360
=> 260 + ∠BOA = 360
=> ∠BOA = 360 - 260
=> ∠BOA = 100
Now, in traingle OPB and OPA,
AP = BP {tangents froma point}
OA = OB {Radii of the circle}
OP = OP {common side}
By SSS congruent criterian,
ΔOPB ≅ ΔOPA
Hence, ∠POB = ∠POA {by CPCT}
Now, ∠POA = ∠AOB/2 = 100/2 = 50
