1. The problem statement, all variables and given/known data three point charges, each of 10^-9 are located at 3 corners of a square of side 20cm. Calculate the electric potential at the forth corner. 2. Relevant equations V = Q / (4(pi)(epsilon 0) r) 3. The attempt at a solution Potential because of corner A = 10^-9 / (4 (pi) (epsilon 0) 0.2) = 44.96 Potential because of corner B = 10^-9 / (4 (pi) (epsilon 0) 0.2) = 44.96 Potential because of corner C = 10^-9 / (4 (pi) (epsilon 0) 0.284) = 31.66 A + B + C = 121.58 Is this correct, finding the potential from each point charge individualy? Also there is another question very similar to this where there are 4 point charges on the corners of a square, and we need to find the potential at the centre, would i do this the same as above, (providing what i did above is correct.