$4\sqrt{ 16 \times 3 }$
Write the expression in exponential form with the base of $4$$4\sqrt{ {4}^{2} \times 3 }$
The root of a product is equal to the product of the roots of each factor$4\sqrt{ {4}^{2} }\sqrt{ 3 }$
Reduce the index of the radical and exponent with $2$$4 \times 4\sqrt{ 3 }$
Calculate the product$\begin{align*}&16\sqrt{ 3 } \\&\approx27.71281\end{align*}$