The volume of any cube can be calculated as:

Where a is the width, height, and length of the cube.
So, if the volume is 125 ft cubed, the value of a can be calculated as:
![\begin{gathered} 125=a^3 \\ \sqrt[3]{125}=a \\ 5=a \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/km6fz7jlvd1esgl0i9ip6ifwqqlybhvm0w.png)
Therefore, the width is 5, height is 5 and the length of the square chest is 5.