The volume of a sphere is defined as: V=(4*pi*r^3)/3 then, if we double the radius of the sphere (r=2r): V=(4*pi*(2r)^3)/3 V=(4*pi*(2^3*r^3))/3 V=(4*pi*r^3)/3*8
Then, the answer is that if you double the radius of the sphere, its volume is increased 8 times.
