Hi;

here is a problem that has been buzzing at the back of my head for years. I think it would be easy to solve it with calculus, but I have been told there is a common-sense solution using just elementary geometry, and that is what I am looking for. But I don't even know where to begin.

The problem goes like this:

There is a vertical signboard of height positioned so that its lower edge is at height above the ground. How far from it should I stand so the angular width (heigth, actually) of the sign as seen by my eyes is greatest?

For simplicity, let's assume my eyes are at ground level.

TIA, LL.