Calculating Electric Potential Energy of a Charge Configuration

[squintyeyes]

how would you solve this problem?

A charge q1 = 3.40 nC is placed at the origin. Three identical charges, q2, q3 q4, are placed at the positions (0.100 m, 0 m), (0 m, 0.100 m), and (0.100 m, 0.100 m). What is the potential energy of this configuration of charges?

should you do answer = 4kq^2/r or something else?

 

[annumarch]

take all possible combinations of any two charges and find their potential energues using kQ1 Q2/r and add all the these/