Final answer:
The specific gravity of the granite sample is 2.8.
Step-by-step explanation:
The ratio of a substance's density to that of a reference substance, typically water, is what is used to determine the substance's specific gravity.
The specific gravity of the granite can be found by dividing its density by the density of water. The specific gravity is a dimensionless quantity that represents the ratio of the object's density to the density of water.
To find the specific gravity, divide the density of the granite (2.8 g/cm³) by the density of water (1.0 g/cm³):
Specific gravity = 2.8 g/cm³ / 1.0 g/cm³ = 2.8
Therefore, the specific gravity of the granite sample is 2.8.