Final answer:
The actual mass of a 1cm² piece of copy paper is 4.5 g/cm².
Step-by-step explanation:
To find the actual mass of a 1cm² piece of copy paper, we can use the concept of area. If the actual mass of a sheet of copy paper is 4.5 g, we can assume that the mass is uniformly distributed across the entire sheet.
Therefore, the mass per unit area of the copy paper is 4.5 g divided by the total area of the sheet. If the sheet is square, with each side measuring 1cm, then the total area is 1cm x 1cm = 1cm².
So the actual mass of a 1cm² piece of copy paper would be 4.5 g divided by 1cm², which is equal to 4.5 g/cm².