Answer
$a_{4}=-\frac{1}{3}$
Work Step by Step
The nth term of a geometric sequence can be found using the formula:
$a_n=a_1(r^{n-1})$
where
r= common ratio
$a_1$ = first term
$a_n$ = nth term
n = term number
Substitute the given values of $a_1$, n, and $r$ to find:
$a_{4}=9(-\frac{1}{3})^{4-1}
\\a_{4}=9(-\frac{1}{3})^{3}
\\a_{4}=9(-\frac{1}{27})
\\a_{4}=-\frac{9}{27}
\\a_{4}=-\frac{1}{3}$
