To simplify \(3 \sqrt{27}\), first, simplify the square root of 27.
We can break it down as follows:
\[ \sqrt{27} = \sqrt{9 \cdot 3} = \sqrt{9} \cdot \sqrt{3} = 3\sqrt{3} \]
Now, substitute back into the expression:
\[ 3 \sqrt{27} = 3 \cdot (3\sqrt{3}) = 9\sqrt{3} \]
Thus, the simplified form of \(3 \sqrt{27}\) is:
\[ \boxed{9\sqrt{3}} \]