1. The problem statement, all variables and given/known data There is a 4 cm by 3 cm rectangle with 2.0 nC charges at three corners. I'm trying to find the electric potential of the last corner in V. 2. Relevant equations U=(kQq)/r I think V=(kq)/r I think 3. The attempt at a solution I found the U's between the know corners but i don't know where to go from there.