Tangent is perpendicular to the radius at the point
Here PA is tangent segment and OA is radius of circle
OA ⟂ PA
∠OAP = 90°
Now in Triangle OAP, OP2 = OA2+ PA2 (pythagoras theorem )
OP2 = OA2+PA2
2 = 2+PA2
= +PA2
PA2 = -
=
PA = √ = cm