Here is a drawing: http://imgur.com/VdW1Xmv
Trying to solve this question. I understand that the charge in the center needs to be positive, and the sum of all forces should be 0.
But how do I express the magnitude of the charge in the center, how do I find it? I know vectors need to be used, but not sure between which charges, just between the electrons to the positive charge, or all the vectors between all 5 charges?
Help please, so confused.