Charges of 4.0 µC and -6.0 µC are placed at two corners of an equilateral triangle with sides of 0.10
m. At the third corner, what is the electric field magnitude created by these two charges?
the distance from each charge is 0.10 meter
so the field strength magnitude of each is
k Q1/.1^2 and k Q2/0.01
but their directions are (180 - 60 = 120) degrees apart