There is a cylindrical gas tank (42lbs/ft^{3})4ft tall and with a diameter of 3ft. It is being carried on the back of a truck, horizontally. How much work would it take to empty the entire tank to another tank 5ft above the top of the original tank?

I originally tried solving with the tank lying horizontally but it didn't look like it would be easy trying to find a function for the volume of prices sliced horizontally. I reasoned that because the volume was the same, it wouldn't be different to just think of the tank ad being vertical. I did the problem that way and was incorrect which leads me to believe that my assumption about its orientation not mattering to be wrong.

I would really appreciate some assistance with this.

The correct answer is 2457pi and I got 2646pi.