Answer:
8.5
Explanation:
So the line segment that is tangent to the circle is 8, and AO is 11.7.
When you connect them, they are perpendicular, so you have a right triangle with one unknown leg that we will call X, a leg that is 8, and a hypotenuse that is 11.7.
If you use the Pythagorean Theorem, you will find that the leg is √72.89, which is approximately 8.5.
That leg is the radius.
This might be wrong so check it.