We have a cube as follows which has a sphere inside in the following two ways:
Assume that the cube and sphere are identical in both cases.
Is the packing fraction different in these two cases?
No
We know that packing fraction is intuitively the amount of occupied space inside a given unit cell.
In this case, this cube is our unit cell and we have one sphere of same radius in both cases.
So, amount of space occupied will be the same in both cases, since the volume remains same.
Hence, the packing fraction will not change.