Electrostatic and Gravitational Force Equilibrium

Two identical conducting spheres, each with a mass of 10 g, are suspended by identical insulating threads. After being given equal charges, the spheres repel and hang in equilibrium, with each thread making an angle θ with the vertical. When the charge on each sphere is tripled, the angle with the vertical becomes 2θ. Which equation correctly relates the electric force, $F_e$, to the gravitational force, $F_g$, when the system is in its initial equilibrium at angle θ?