
Step-by-step solution-:
By using the Geometric Mean (Altitude) Theorem:

(CD)^2=AD\times{DB}
Substitute the CD=12, AD=x, and DB=16 into the Geometric Mean (Altitude) Theorem:
\textcolor{primary}{12^{2}}=\textcolor{secondary}{x}\cdot \textcolor{tertiary}{16}\implies144=16x
After solving:
16x=144\implies x=\frac{\cancel{144}}{\cancel{16}}=9
The value of x is 9:
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