Question 946353
x,  side length of square bottom,
h,  how tall the box.


Total area for the FIVE surfaces:  {{{x^2+4hx}}}.


Volume:  {{{x*x*h=60}}}
{{{hx^2=60}}}.


{{{h=60/x^2}}}, substitute into the total area expression:
{{{x^2+4(60/x^2)x}}}
{{{highlight(x^2+240/x)}}}