Final answer:
The density of metal A is 7.21 g/cm³, representing the value rounded to three significant figures.
Step-by-step explanation:
The density of metal A, expressed in grams per cubic centimeter (g/cm³), should be reported with the same number of significant figures as the measurement with the fewest significant figures.
In the given problem, if a metal has a mass measurement with four significant figures and a volume measurement with three significant figures, the calculated density must be rounded to three significant figures. Therefore, the density of metal A is 7.21 g/cm³.