A small plastic ball with a mass of 6.15 x 10-3 kg and with a charge of +0.158 µC is suspended from an insulating thread and hangs between the plates of a capacitor (see the drawing). The ball is in equilibrium, with the thread making an angle of 30.0° with respect to the vertical. The area of each plate is 0.0157 m2. What is the magnitude of the charge on each plate?