Subject: Re: Distance to the horizon
Date: Wed, 29 Jan 1997 21:00:49 -0500
From: Alex Bogomolny
If you are interested in the straight-line distance, then the formula is exactly the same. Only now, a=200" instead of 6". Thus you get an additional factor of sqrt(200/6)=5.8. If the fellow was 200" tall he would see the horizon at 5.8*3.1=17.9 mi. But now you have to add the two quanitities because your observer and the island are located on different sides from the horizon. So that the total is 17.9+3.1=21.
To get the surface distance you must use some trigonometry. It will be more than 21 mi but not by much.