You provided measurements in inches:
Width: 72" (182.88cm)
Height: 24" (60.96cm)
Depth: 28" (71.12cm)
Your tank's volume is approximately 48384 cubic inches or 209.45 U.S. gallons, which is approximately 814.78 liters.
A cylindrical tank with diameter 4 ft and height 6 ft has about 75.4 cubic feet. 75.4 (cu feet) = 564.031 US gallons but that answer is too accurate (too many significant figures). How accurately did you measure the tank dimensions? If it is only to the nearest foot (one significant figure) than the answer would be: 600 gallons (one significant figure) If the tank was rectangular then we are missing a dimension (the length).
A round tank that is 6ft 6inches wide by 4ft deep holds 1,150 US gallons.
763.6 gallons-6.2 gallons /cubic foot
A 4' x 4' round tank holds 375.5 gallons.
89.8 gallons for every foot of depth.
24.5 gallons to fill up
72 gallons is needed to fill the tank.
About 10 gallons.
The tank holds 17 gallons total.
A replacement fuel tank is 27 gallons, so a couple of gallons less should fill it up.
Approximately 43 gallons
Tank capacity is twenty gallons.
25 Gallons will fill the tank for a Toyota 4Runner
Just filled up the tank for the first time and the tank was nearly empty. I'm guessing the tank is about 12 gallons, because it took about 11.5 gallons to fill it up.
7 gallons
Fill your tank, calculate the miles to the next service station, and see how many gallons you need to re-fill the tank.