Question

The radius r of the nucleus of an atom of mass number A is r = 1.2A1/3 femtometers. Find A if r = 3.6 femtometers.

Answer 1

solve for A
A = 3r/1.2
plug in r = 3.6

Answer 2

A = 3(3.6)/1.2
A = 10.8/1.2
A = 9

Answer 3

thats an integer value which is good for a mass number. looks correct