The fields and their components are shown in the figure.

E_{x} = E_{2x} - E_{3x} = (2.25 - 1.59)X10^{4}
= 0.66 X10^{4} N/C

E_{y} = E_{3y} = 1.59X10^{4} N/C

E = (E_{x}^{2} + E_{y}^{2})^{½}
= [(0.66)^{2} + (1.59)^{2}]^{½}X10^{4}
= 1.72X10^{4} N/C

q = tan^{-1} E_{y}/E_{x}
= tan^{-1} 1.59/0.66 = 67.5º