To solve \( 3^{-4} \) using the property of negative integer exponents, we can use the rule that states \( a^{-n} = \frac{1}{a^n} \).
Applying this property:
\[ 3^{-4} = \frac{1}{3^4} \]
Next, we calculate \( 3^4 \):
\[ 3^4 = 3 \times 3 \times 3 \times 3 = 81 \]
So, we substitute back into the equation:
\[ 3^{-4} = \frac{1}{81} \]
Thus, the answer is:
\[ 3^{-4} = \frac{1}{81} \]