What is the density of an object that has a mass of 8mg and a volume of 5.5m

The formula of density is:

Density = mass (in kg) / volume (in m^3)

So we need to convert 8 mg to kg.

8 mg = 0.000008 kg

So using the density formula

Density = mass / volume

Density = 0.000008 kg / 5.5 m^3

Density = 0.0000014545 kg/m^3

Density = 1.4545 x 10^-6 kg/m^3