let's take radius of the basket ball as b
let's take radius of the tennis ball as t
b = 3.6 t
volume of the basket ball vb = 4/3 pi b^3
volume of the tennis ball vt = 4/3 pi t^3
therefore
vb / vt = b^3 / t^3
= (3.6t)^3 / t^3
= 3.6^3
= 46.656
so the volume of the basketball is 46.656 times greater than the volume of the tennis ball.