A spherical balloon is made from a material whose mass is 3.91 kg . The thickness of the material is negligible compared to the
1.33-m
radius of the balloon. The balloon is filled with helium
(He)
at a temperature of 287 K and just floats in air, neither rising nor falling. The density of the surrounding air is
1.19k(g)/(m^(3))
. Find the absolute pressure of the helium gas.