What is the legal distance required for shortening the prayer? And where does the boundary for shortening…

Answer

In the name of Allah, the legal distance is approximately 43 kilometers and one-fifth of a kilometer. As for the boundary for shortening, it is determined by the disappearance of the adhan and the walls. The disappearance of the adhan means that the sound from the minaret, without modern instruments, cannot be heard from the mosque in the area considered as the last point of that city. Also, the walls should not be distinguishable, only seen as a vague outline. This is easy for anyone with functioning sight and hearing. Allah knows best.