Answer
$r= \dfrac{3}{2}$
Work Step by Step
The common ratio $r$ can be found by dividing a term by the previous term.
Thus, the common ratio of the given sequence is:
$r=\dfrac{\frac{9}{2}}{3}
\\r= \dfrac{9}{2(3)}
\\r=\dfrac{9}{6}
\\r= \dfrac{3}{2}$