The volume of a cone is (1/3)·(π)·(radius)²·(height) .
For the cone in this problem,
Volume = (1/3) (π) (5 cm)² (2 cm)
Volume = (π/3) (25 cm²) (2 cm)
Volume = 50π/3 cm³ .
Density = (mass) / (volume)
Density = (6g) / (50π cm³/3)
Density = 18/50π g/cm³
Density = 0.115 g/cm³