Question 1005800
What kind of shape is your plate?  Usually "plate" means something like a disk or very short cylinder.  Yours seems to be rectangular.  You gave three values to describe it instead of just two (as for cylinder).



Going with that,
Given x, y, z, known dimensions of the plate, find s, the edge length of the cube with the same volume:
{{{v=x*y*z=s^3}}}


{{{highlight(s=root(3,xyz))}}}