Question 855140
Think of 20 liters as {{{20*1000*cm^3}}}.


If d is the diameter, then the radius is {{{d/2}}}.
{{{30*pi(d/2)^2=20000}}}
If you can understand the conversion and the forming of the equation, then you are ready to solve for d; otherwise, you might need a little bit more help.



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Please understand, the pi is NOT intended as an exponent.  It just looks like in a raised position, a fault of this rendering.  pi is a factor.