We were given a 12 cm by 12 cm area of aluminum foil (it weighed 0.60 g) and were told to calculate the atomic mass of Aluminum atoms given that the radius of 1 aluminum atom is 143 picometers and the density is 2.7 grams per centimeter cubed, without using Avogrado's number. How do I go about doing this?

Question

We were given a 12 cm by  12 cm area of aluminum foil (it weighed 0.60 g) and were told to calculate the atomic mass of Aluminum  atoms given that the radius of 1 aluminum atom is 143 picometers and the density is 2.7 grams per centimeter cubed, without using Avogrado's number. How do I go about doing this?