What's the bearing of point q from p if a man starts from point p and walks 8 kilometers on a bearing of 034° to point r and then walks 12 kilometers on a bearing of 107° from r to q?

In order for the function to be linear, what must m be and why? m = 22 because the rate of change is 1. m = 20 because the rate of change is 3. m = 22 because the rate of change is -1. m = 20 because the rate of change is -3.