It might be 90in
Because it’s asking if the prism below
Eg: 24936
Place value of 4 is 4x10 raised to the power of 3 or 4000
H=2ft
d=6 ft
r=d/2
r=6/2=3ft
V= π•r^2•h
V=3.14•3^2•2
V=3.14•9•2
V=56.52 ft3
V~56.5ft3
Hi there!
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I believe your answer is:

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Here’s why:
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Hope this helps you. I apologize if it’s incorrect.
V=(4/3)pir^3
find smaller
V=(4/3)pi8^3
V=(4/3)pi512
V=(2048/3)pi
twice of that
Vbig=2*(2048/3)pi
Vbig=(4096/3)pi
find radius
(4096/3)pi=(4/3)pir^3
divide both sides by pi
(4096/3)=(4/3)r^3
times both sides by 3
4096=4r^3
divide both sides by 4
1024=r^3
cube root both sides
8∛2=r
aprox
10.0794
the answer you are looking for is 8∛2 or 10.0794in or something close to that