1. The problem statement, all variables and given/known data One side of a square has length 2.0 cm. In three of the square's corners, there are point charges. Top left corner: -1.0 nC (call this A) Bottom left corner: 10 nC (call this B) Bottom right corner: -1.0 nC (call this C) The top right corner has no charge, and is labelled P. What is the magnitude of the electric field at point P? 2. Relevant equations Electric Field = KQ/r2 3. The attempt at a solution Electric Field Due to A: K(-1.0 x 10-9 C)/(0.02 m2) = -22475 N/C, left Electric Field Due to C: Same as above, but this time the direction is down Electric Field Due to B: First calculate the distance from B to P. This is 0.022+0.022 = 0.0008. Take the square root of 0.0008 to find 0.0282 m. K(10 x 10-9 C) / (0.0282)2 = 112375 N/C, at a 45 degree angle pointing north east. Now, take the sum of all three parts to find the net electric field. A and C together point south west, with a magnitude of 31784.44 N/C. 112375 N/C - 31784.44 N/C = 80590.55 N/C, north east. However, the answer given on the page is not what I got. What went wrong?