The surface area of a sphere is 
and if the original S.A was is enlarged to have it 9 times greater, the radius would be multiplied by 3 or roughly 2.99626 rounded off to 3.0.
For example, let us assign values.
Let A=90
A= 90*9 = 810
and 
the first r is 2.68 and the second r is 8.03
then,
or rounded off to 3.
For example, let us assign values.
Let A=90
A= 90*9 = 810
the first r is 2.68 and the second r is 8.03
then,