Question

Walter puts 1050 cubic inches of dirt into the tank shell and draw a line to show the height of the dirt in the tank

Answer 1

that line could have an infinite possibilities of height, for example if the tank is cubic, 20 inches per side, then we can calculate the line's height:

volume = 20*20*height

given the fact that the tank has 20 inches per side, and we know the volume as a data given:

1050 = 20*20*heigth

hence the height is:

height = 1050/400

height = 2.63 inches