The total mass of helium in a balloon is 199 kg. What is the volume of the balloon? Enter only the numeric portion of the answer, not the units. That is the problem. Im having trouble locating a simple forumla for this. All I can seem to find involve having the radius of the balloon which I do not have. In the book it says each cubic foot of helium can lift .069 lb, so this may play a factor but im unsure of how exactly. I have thought about converting 199KG to lbs and dividing by .069. Is this thinking correct?