Simplify 2 fourth root of 16* fourth root of 4

$2 \sqrt[4]{16} \cdot \sqrt[4]{4}$

Rewrite $16$ as $2^{4}$ .

$2 \sqrt[4]{2^{4}} \cdot \sqrt[4]{4}$

Pull terms out from under the radical, assuming positive real numbers.

$2 \cdot 2 \cdot \sqrt[4]{4}$

Multiply $2$ by $2$ .

$4 \cdot \sqrt[4]{4}$

Rewrite $4$ as $2^{2}$ .

$4 \cdot \sqrt[4]{2^{2}}$

Rewrite $\sqrt[4]{2^{2}}$ as $\sqrt{\sqrt{2^{2}}}$ .

$4 \cdot \sqrt{\sqrt{2^{2}}}$

Pull terms out from under the radical, assuming positive real numbers.

$4 \sqrt{2}$

The result can be shown in multiple forms.

Exact Form:

$4 \sqrt{2}$

Decimal Form:

$5.65685424 \dots$