Physics
posted by Ivan .
Four identical 12µC charges are placed at the corners of a square of sides 44 cm, with one additional 12µC charge placed at the center. Find the electric potential at the midpoint of one of the sides.

Add up the kQ/r values contributed by each of the five charges (four at the corners and one in the middle of the square). The distances (r) of the different charges will vary. Three of them are located a distance of 0.22 m away.
You will have to do a bit of geometry for distances of the other two. Drawing a figure will help.
k is the Coulomb's Law constant. I am sure you have heard of it.