Answer
The common ratio is $r=\frac{3}{4}$.
Work Step by Step
The given sequence is
$128,96,72,54,...$
Calculate the ratio between each pair of consecutive terms.
$\frac{96}{128}=\frac{3}{4}$
$\frac{72}{96}=\frac{3}{4}$
$\frac{54}{72}=\frac{3}{4}$
Hence, the common ratio is $r=\frac{3}{4}$.
