[ProudFossil]

Your correct it is an irrational number. But this will get you close enough. 5.241482788417793 cubed

Thank you for getting closer to the answer. But I don't think my $8 calculator has enough decimal places to find the correction for you latest approximation so I fully accept your solution. (I think I read that some computer geek has calculated pi to something like 1,500,000 decimal places) Anyway onward and upward with the true wonder of math.

[DaveTesla]

You might be interested in this:
Math Symbols in HTML
http://comers.citadel.edu/math_sym2005.htm#operation

http://cat.xula.edu/tutorials/html/subandsup