[tex]V_{d} = (a_{d})^{3} = 64 \ cm^{3}\\\\(a_{d})^{3} = 64 \ cm^{3}\\\\a_{d} = \sqrt[3]{64 \ cm^{3}}\\\\\underline{a_{d} = 4 \ cm}\\\\\\a_{m} = \frac{1}{2}a_{d}= \frac{1}{2}\cdot4 \ cm\\\\\underline{a_{m} = 2 \ cm}\\\\V_{m} = (a_{m})^{3} = (2 \ cm)^{3}\\\\\boxed{V_{m} = 8 \ cm^{3}}[/tex]
