Question 537539
A small beach ball has a radius of 8 inches. A larger beach ball has a volume that is twice the volume of the small ball. What is the best approximation for the radius of the large beach ball?
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Let r = radius of the large ball
:
{{{4/3}}}*{{{pi*r^3}}} = 2({{{4/3}}}*{{{pi*8^3}}})
Multiply both sides by 3, to get rid of the denominators, find 8^3
4({{{pi*r^3}}}) = 8({{{pi*512}}})
divide both sides by {{{4*pi}}}, results
r^3 = 2(512)
r^3 = 1024
r = {{{3sqrt(1024)}}}; (cube root)
r = 10.08 inches, radius of the larger 
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Check this on a calc
(4/3)*pi*8^3 = 2144.66 cu in
(4/3)*pi*10.08^3 = 4290.12, close enough