# How do you find the 9th term in the geometric sequence 4.5, 9, 18, 36, ...?

Here a (first term) = 4.5 and r (common ratio) $= \frac{9}{4.5} = 2$
to find any term in the sequence use : ${u}_{n} = a {r}^{n - 1}$
$\Rightarrow {u}_{9} = 4.5 . {2}^{8} = 1152$