Solution:
Given:
Using the secant-secant theorem,
If two secants are drawn from an external point to a circle, then the product of the measures of one secant's external part and that entire secant is equal to the product of the measures of the other secant's external part and that entire secant.
Thus;
Hence,
[tex]\begin{gathered} 6(6+12)=5(5+x) \\ 6(18)=5(5+x) \\ 108=5(5+x) \\ \frac{108}{5}=5+x \\ 21.6=5+x \\ 21.6-5=x \\ x=16.6cm \end{gathered}[/tex]
Therefore, x = 16.6cm
