Problem $1.$

Three charged particles are located at the corners of an equilateral triangle, as shown in the figure below. Calculate the magnitude and direction of the total electric force exerted on the $\backslash (7\backslash$mu $\backslash$mathrm$\{$C$\}\backslash )$ charge.

Figure $1$: Three charged particles at the corners of an equilateral triangle. The charge $\backslash ($ q$\_\{1\}=7\backslash$mu $\backslash$mathrm$\{$C$\}\backslash )$ is the charge of interest.