It's just a simple division of 10 (as there are 10 layers of suared centimtres per cubic centimtre). But then you probably knew that any way!

also, 1.151g/cm squared is just what it says - 1.151 grams per centimetre squared (or 1.151g/cm^2). Converting this to cubic centimtres is just multiplying it by 10 ie, 11.51g/cc (or 11.51g/cm^3).