Question

Three forces are applied to an object, as shown in the figure. Force has a magnitude of 21.3 newtons (N) and is directed 30.0° to the left of the +y axis. Force has a magnitude of 12.0 N and points along the +x axis. A third force is applied such that the vector sum of the three forces is 0 N. What are (a) the magnitude and (b) direction of this third force ? Specify the direction as a positive angle relative to the negative x axis, as shown in the figure.