According to the triangle proportionality theorem, we have,
[tex]\text{if BC}\parallel DE,\text{ }\frac{AD}{AB}=\frac{AE}{EC}[/tex]
Substituting the values, we get,
[tex]\begin{gathered} \frac{20}{5}=\frac{16}{x} \\ 4=\frac{16}{x} \\ x=\frac{16}{4}=4 \end{gathered}[/tex]
Thus, the value of x is 4.
