1. The problem statement, all variables and given/known data For a nucleus of A=220, estimate very roughly how many nucleaons would be at the surface. 2. Relevant equations R0=1.5 x 10-15 r=A1/3 x R0 3. The attempt at a solution Using the formulas, I calculated R to be 7.2441729 x 10-15 The book says that the number of nucleons at the surface and the total number of nucleons has a ratio of ~1/r 1/r= 1.3804 x 1014 I tried the following: 1.3804 x 1014 = 220/x which didn't make sense... what am I doing wrong? Thanks!