Answer
The direction of the net electric field is at an angle of $45^{\circ}$ above the positive x axis.
Work Step by Step
By symmetry, the electric fields due to particle 1 and particle 2 cancel out.
The net electric field is equal to the electric field due to particle 3.
Since the electric field due to a positive charge is directed away from the positive charge, the direction of the net electric field is at an angle of $45^{\circ}$ above the positive x axis.
