Final answer:
Each additional cup adds the height of one cup to the total height of the stack. Since the volume of one cup is defined as 9 in.³, the height each cup adds is determined by dividing the volume by the length and width dimensions.
Step-by-step explanation:
To determine how much height each additional cup contributes to a stack, we assume the first cup sets the base level. If we have a stack of cups with a volume of 9 in.³ each and a given volume is equal to the product of length, width, and height, we can find out how tall each stack is by dividing the volume by the product of the length and width.
Since the volume of each stack is constant, every additional cup will add to the height by the same amount, which is the height of one cup. For this stack of bills, with a volume of 9 in.³ per stack and 108 stacks giving a total volume, the height of the money will be about 100 inches high as determined by the provided equation.