Two identical conducting spheres each of mass 10 g are suspended from separate, identical insulating threads of equal length. When both spheres carry equal charges, they repel each other and each thread makes an angle θ with the vertical at equilibrium. If the angle θ doubles (i.e., becomes 2θ) when the charge on each sphere is tripled, what equation relates the electric force $$F_e$$ and gravitational force $$F_g$$ at the original angle θ?