



 
Hi Tom, I think you missed the fact that the tank is lying on its side, "its axis is horizontal". Penny Tom replied
Tom, I redrew my diagram with a line across the end of the tank half way up and used red to colour the region from 1/2 way up to 3/4 the way up. If your contention is correct then the area of the piece coloured red is equal to the area of the piece coloured gray. But this is certainly not true. They are the same height, 3 inches, but the red part is wider than the gray part. To see how to calculate the area look at my response to a question from Mario concerning another horizontal cylindrical tank. Penny  


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