Three glasses are placed by a waiter on a light-weight tray. The first glass has a mass of M1 = 575 g and is located R1 = 18 cm from the center of the tray at an angle θ1 = 45 degrees above the positive x-axis. The second glass has a mass of M2 = 450 g and is located R2 = 24 cm from the center of the tray at an angle θ2 = 55 degrees below the positive x-axis. The third glass has a mass of M3 = 275 g and is located R3 = 19 cm from the center of the tray at an angle θ3 = 45 degrees above the negative x-axis. A fourth glass of mass M4 = 850 g is to be placed on the tray so that the center of mass is located at the center of the tray.