How long is a 7500 gallon tank 9'9 DIAMETER?

Answer 1

The radius of the pipe is 4.875 feet.
The area of the cross-section is
pi * r^2
= 23.765625 * pi foot^2

The volume per foot of length is
cross-section * length
= (23.765625 * pi foot^2) * 1 foot
= 23.765625 * pi foot^3

There are roughly 7.481 gallons/cubic foot, so one foot of length contains roughly

(7.481 gallons/(foot^3)) * (23.765625 * pi foot^3)
= 7.481 * 23.765625 * pi gallons
= 558.55 gallons (not exact)

So to contain 7500 gallons the tank must be

7500 gallons / (558.55 gallons / foot)

= 13.43 feet long (not exact)