Answer:
Explanation:
step 1
Find the radius of the circle
Remember that AB is a tangent to the circle at point B
so
AB is perpendicular to OA
The radius of the circle is equal to the segment OA
In the right triangle OAB


substitute the values

step 2
Find the value of p
In the right triangle OPQ
see the attached figure to better understand the problem
Applying the Pythagoras Theorem

substitute the values
Remember that OP is the radius





simplify