The mass of 1 cm² piece of copy paper is 0.0072 g.
Assuming the dimensions of a piece of paper is 21.0 x 29.7 cm
The area of the piece of paper = 21.0 * 29.7 = 623.7 cm²
Mass of 623.7 cm² = 4.5 g
Mass of 1 cm² piece of copy paper = 4.5/623.7 cm² = 0.0072 g
Therefore, the mass of 1 cm² piece of copy paper is 0.0072 g.
Learn more about area at: https://brainly.com/question/25965491
#SPJ1