if $x>1$ and $\log\_2x,\log\_3x,\log\_x16$ are in Geometric progression then what is x equal to?

Solution:  

$(\log\_3x)^2=\log\_2x\times\log\_x16=\log\_216=\log\_22^4=4$  

$\log\_3x=2 or x=3^2=9$  

so my doubt is how $(\log\_3x)^2=\log\_2x\times\log\_x16$ while the rest i have understood