Final answer:
The density of the nickel is approximately 11.8 g/cm³.
Step-by-step explanation:
The density of a substance is calculated by dividing its mass by its volume. In this case, the mass of the nickel is 65.8 g and the volume is 5.56 cm³. To find the density, we divide the mass by the volume:
Density = mass/volume
Density = 65.8 g / 5.56 cm³
Density ≈ 11.8 g/cm³