Final answer:
The most meaningful way to compare the cost of a plastic product is by cost per cubic inch. This measures the density of the product, which is the mass per unit volume, usually expressed in grams per cubic centimeter (g/cm³ or g cm⁻³).
Step-by-step explanation:
The most meaningful comparison in estimating the cost of a plastic product is cost per cubic inch. When comparing the costs of plastic products, it is essential to consider the volume of the material because plastics are often sold by volume, and the density of the plastic affects the amount of material used. Therefore, we are comparing the mass per unit volume, which is the density. For example, measuring the weight of a cubic centimeter of wood and comparing the densities in grams per cubic centimeter (g/cm³ or g cm⁻³) helps to understand the amount of material and its cost. A cubic centimeter (cc) is equivalent to one milliliter (mL), making conversions between units easier.