Shadow

Have you ever watched the path of the shadow of somebody walking past a lamppost? What path does the end point of the shadow take? How long is the shadow?

Given: that the pavement is flat, that I walk a straight line passing the lamppost at a distance D, that the height of the lamppost is H and that I am of height h; what is the distance y from the line of my path to the end point of my shadow with respect to x, the distance I am from the line of the lamppost? How long is my shadow with respect to x?

Answers to John Rowland