One size of cardboard can be purchased in sheets that are 3/16 inches thick. The sheets of cardboard are stacked on top of each other in packages. The height of each stack is 2 1/4 inches.
Part A: Use the model of a ruler to determine the number of sheets of cardboard in a stack.
Part B: Explain how you used the model to find your answer.
Part C: Write an expression that can be used to determine the number of sheets of cardboard in a stack.
Part D: Explain how your expression relates to the model.​