Working from the information provided in the question, it could be any number at all.
39
3
nine
None of the graphs that I can see!
Imagine 4squared (16) divided by 4 (4). Therefore units squared divided by units would be units.
39
201
7 squared and 3 squared. 49 - 9 = 40
The difference is 39.
3
64 - 25 = 39
well if you doubled the coils it would be pie times the amount of voltage in the current squared
the new area will be fourfold, not doubled. try it on squared paper and see how the shape increases from one square into four...
nine
1
None of the graphs that I can see!
its an exponent it means squared or doubled because its a 2