Finding tension given densities?

[LOannie234]

An empty rubber balloon has a mass of
0.0132 kg . The balloon is filled with helium
at a density of 0.185 kg/m3
At this density .
the balloon has a radius of 0.474 m .
If the filled balloon is fastened to a vertical
line, what is the tension in the line? The
acceleration of gravity is 9.8 m/s^2

I calculated the Weight of the displaced Air = Volume of Sphere shaped balloon x Density of Air x g

AIr Density = 1.29 kg/m^3
Volume of Sphere = (4/3) pi r^3
r= 0.474mand then subtracted the weight of the balloon = Mass of Balloon x g = 0.0132 Kg x 9.8 m/S^2
and it didnt work... :( any help would be awesome!

 

[eczeno]

helium has mass.