#### Answer

$\frac{1}{81}$

#### Work Step by Step

$\frac{1}{1}$, $\frac{1}{3}$, $\frac{1}{9}$, $\frac{1}{27}$
Every next fraction's denominator is obtained by multiplying 3 in previous fractions denominator
So next fraction $\frac{1}{27 * 3}$ = $\frac{1}{81}$