![\"\"](\"/userfiles/image/steps_images/step1.JPG\")
Given that AB = 18.Let Q be the point on the circle C.
\Hence,Q be the point on sphere A.
\AB is the radius of the sphere.
\Draw a line from A to Q.
\Hence,AQ also be the radius of the sphere.
\AB = AQ
\AQ = 18 (AB = AQ)![\"\"](\"/userfiles/image/steps_images/solution.JPG\")
The value of AQ is 18 units.