Three point$-$like charges are placed as shown in the figure, $a=36\mathrm{.}0cm$ and $b=66\mathrm{.}0cm.$ The charge $(q_3)$ is placed

half way on the $($b$)$ side. Find the magnitude of the electric field at the top left corner. Let $q_1=-1\mathrm{.}20C,q_2=-2\mathrm{.}70C,$

and $q_3=-4\mathrm{.}50C.$

N$/$C