In[]:=
V=Quantity[1,"Volts"];​​A=Quantity[1,"Amperes"];​​Manipulate[​​soln=Solve[VsV==IsA*Rs*G,{Rs}],​​{{Vs,5},ControlType->InputField},​​{{Is,0.02},ControlType->InputField},​​{{G,100},ControlType->InputField}​​]
Out[]=
​
Vs
5
Is
0.02
G
100
Rs
2.5V
A
