Final answer:
The density of a material with a volume of 15.6 cm³ and a mass of 12.1 g is calculated to be 0.775 g/cm³, which rounds to approximately 0.78 g/cm³, making answer A) 0.78 g/cm³ correct.
Step-by-step explanation:
To calculate the density of a material, you divide the mass by the volume. In this case, if a material has a volume of 15.6 cm³ and a mass of 12.1 g, its density would be calculated as follows:
Density = Mass ÷ Volume
Density = 12.1 g ÷ 15.6 cm³
Density = 0.775 g/cm³
When rounded to two decimal places, the density is approximately 0.78 g/cm³. Therefore, the correct answer is A) 0.78 g/cm³.