Answer
16
Work Step by Step
Based on the definition of $a^{\frac{m}{n}}$, we know that $a^{\frac{m}{n}}=(\sqrt[n] a)^{m}=\sqrt[n] a^{m}$ (where $\sqrt[n] a$ is a real number).
Therefore, $64^{\frac{2}{3}}=\sqrt[3] 64^{2}=(\sqrt[3] 64)^{2}=(4)^{2}=16$
We know that $\sqrt[3] 64=4$, because $4^{3}=64$.
