Explanation:
the density of an object is always
mass / volume
now, what units does your teacher want us to use ? there is no information.
so, I will simply use
grams / cm³
as the volume of cm×cm×cm is cm³.
the volume is
length × width × height =
= 3.7 × 2.4 × 2.1 = 18.648 cm³
the density is then
4.82/18.648 g/cm³ = 0.258472758... g/cm³