I am so happy to have found this forum!

I have a math question that my wife and I are going back and forth with. I didn't know which form to post the question as I didn't know which branch of mathematics it applies.

It is a reference to finding the cost per inch of blown in insulation. I know the square feet, I know how many inches were blown in, and I know the dollar amount. Trying to figure out how much the cost is per square inch.

Any direction would be very appreciative.