Final answer:
The density of the metal cube is 9 g/cm³.
Step-by-step explanation:
The density of an object can be calculated by dividing its mass by its volume. In this case, the cube has a mass of 72 grams and each side measures 2 centimeters.
The volume of the cube is calculated by cubing the length of one side, so in this case it would be (2 cm)^3 = 8 cm³.
Therefore, the density of the metal cube is 72 g / 8 cm³ = 9 g/cm³.