1. The problem statement, all variables and given/known data Under standard conditions, the density of air is 1.293 kg/m3 and that of helium is 0.178 kg/m3. A spherical helium balloon lifts a basket plus cargo of mass 269.0 kg. What must be the minimum diameter of the spherical balloon? 2. Relevant equations p = F/A 3. The attempt at a solution I don't know what equation to use to find F?