Alright I've been stuck on this for the last hour, so given that the black and the red lines are perpendicular, and you know the angle formed by the black and the purple line, is it possible to find the angle between the y axis and the black line, the graph doesn't show the actual intersection point between black and purple, I don't know what the intersection point actually is, and the graph is representative of my friend's dumb made up physics problem.