if an iceberg has a volume of 8660 cubic feet, what is the mass in kg of the iceberg?

I would multiply 8660 ft^3 x density ice (in lbs/ft^3) = total mass in pounds.

Then pounds x 453.6 convert it to grams and divide by 1000 to convert to kg.
You will need to look up the density ice in lb/ft^3 as I don't remember that number.