Solving for Resultant vector and relative Angle

Question

How would you solve the following resultant vector R and angle θ based on the following description (its mentioned that R=A+B+C?):

Starting from central point O on the cartesian plane, going tip-to-tail

Vector A: 72.4 m, N 32° E,

Vector B: 57.3m, S 54°W

Vector C: 17.8 m, S (angle unknown, greater than 109°) W,

R: Length Unknown, heading SW back to point O

Looking to Solve for R and the angle θ it makes relative to the positive Y-axis.

Answer 1

I would create an X,Y chart (or in this case and E-W, N-S chart). Find the EW and NS components of the two known vectors. If they're west or south, enter them as negative in the chart.

It sounds like the Resultant needs to be a 4th vector to make all of the other 3 vectors add up to Zero. The mystery with Vector C makes this challenging. The resultant will depend on C.

But, hopefully this can get you started!