In figure 1, I have a sloped surface (ground/blue) that an angled instrument is shooting a laser (green) at. If this laser is aiming directly below it (on-nadir) how can I find the *combined slope the laser and sloped ground make. Should I be thinking of the blue line as the tangent line of the green laser segment? Should I be thinking of these two line segments as functions or vectors? I'm having trouble trying to characterize what mathematical object I should be thinking about to find the combined slope.
My known quantities are the theta angle displayed in the first figure, the slope of the green line segment (laser), and the legs of the right triangle that make up this slope of the green line segment.
