Answer:
B. 32
Explanation:
The product of the lengths of segments to the near and far circle intercepts are the same, where the length is measured from the point where the secant and tangent meet. The tangent point counts as both circle intercepts, so we have ...
30×30 = 18×(18 +x)
900 = 324 +18x . . . . eliminate parentheses
576 = 18x . . . . . . . . . subtract 324; next, divide by 18
32 = x