You use the volume formula for a sphere, or V=4/3*pi*r³;
so the first balloon (3cm) has a volume of 113.1.
The second balloon (6cm) has a volume of 904.78.
Therefore, you do 904.78-113.1, getting 791.68 cm³
The answer is the 2nd one because you can only fold this object like this and no other way.
The answer to this question is
D.
Take it step by step by doing the 2 fractions on top