Question 97730
A sphere has an area {{{64pi}}}, what is its volume? 
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You need the formulas
{{{A = 4pi*r^2}}} and {{{V=(4/3)pi*r^3}}}

We are given {{{A=64pi}}}, so we substitute in

{{{A = 4pi*r^2}}}
{{{64pi = 4pi*r^2}}}

Divide both sides by {{{4pi}}}

{{{(64pi)/(4pi) = (4pi*r^2)/(4pi)}}}

{{{16 = r^2}}}

Take positive square roots of both sides:

{{{sqrt(16)=sqrt(r^2)}}}

{{{4 = r}}}

Substitute 4 for r in

{{{V=(4/3)pi*r^3}}}

{{{V=(4/3)pi*4^3}}}

{{{V=(4/3)pi*64}}}

{{{V=(256/3)pi}}} 

{{{V=264.9409805}}}

Edwin</pre>