#### Answer

Geometric sequence
$r=\dfrac {4}{3}$

#### Work Step by Step

$\dfrac {\dfrac {64}{27}}{\dfrac {16}{9}}=\dfrac {\dfrac {16}{9}}{\dfrac {4}{3}}=\dfrac {\dfrac {4}{3}}{1}=\dfrac {1}{\dfrac {3}{4}}=\dfrac {4}{3}\Rightarrow r=\dfrac {4}{3}$
Then this is geometric sequence