On paper, make a careful scale drawing of the two rhenium nuclei just after fission, and label the drawing with the distances that you just calculated. if the two rhenium nuclei are nearly touching, this would be consistent with our model of fission, in which the th-228 nucleus fissions into two pieces that are initially nearly at rest. how big is the gap between the surfaces of the two nuclei? (if you have done the calculations correctly, you will indeed find that the gap is a rather small fraction of the center-to-center distance, which means that our simple model for the fission process is a pretty good model.)