Attached picture with the given variables and questions stated.
E = kq / (r^2)
The Attempt at a Solution
I've taken found the linear electric field magnitudes in relationship to the point
q1 = 3.37e-9
q2 = 6.74e-9
q3 = 3.92e-9
r1 = .647m
r2 = 1.941m
E1 = (k*(q1))/(r1) = 72.3540189055
E2 = (k*(q2))/(r2) = 16.0789708679
I am having difficulty figuring out how to calculate the third vector into the total, any thoughts?