1. The problem statement, all variables and given/known data Three electrons form an equilateral triangle 0.800 nm on each side. A proton is at the center of the triangle. 2. Relevant equations U = k[(q_1*q_2)/r] 3. The attempt at a solution I tried to use the following equation: k*[(3e^2)/(0.8*10^-9) - (3e^2)/(0.4*10^-9)] I plugged in 1.602*10^-19 for both e-values, and got the following answer: -6.4*10^-19 Volts However, it says that "I do not have the correct dimensions." I'm not sure what that error means or what I did wrong, so any help would be appreciated.