I can give you an explanation since I can’t real,y see your numbers!, but I’ll do the work if you can comment and tell me the lengths
Basically, find the volume of the rectangular prism (golf ball box) which is V=Bh, then find the V of the sphere ,, V=4/3 Bh
((B= pie r squared))
Then, multiply the golf balls volume by three, and subtract it from the boxes volume. :D