we have the following:
[tex]\begin{gathered} A=8 \\ V=64 \\ L=\frac{V}{A} \\ \end{gathered}[/tex]Therefore,
Part A:
[tex]\begin{gathered} L=\frac{64}{8} \\ L=8 \end{gathered}[/tex]therefore, the length is 8 centimeters.
Part B:
The block would enter if and only if one the sides us 8 centimeters and the other 1.