Answer:
The radius is 9.9 units
Step-by-step explanation:
The picture of the question in the attached figure
we know that
In the right triangle of the figure ABC
Applying the Pythagorean Theorem
[tex]AC^2=AB^2+BC^2[/tex]
substitute the given values
[tex]18^2=AB^2+15^2[/tex]
solve for AB
[tex]AB^2=18^2-15^2\\AB^2=99\\AB=9.9\ units[/tex]
Remember the the side AB of right triangle represent the radius of the circle
therefore
The radius is 9.9 units