# math

posted by
**mike**
.

What's the minimum. length of the arc on the cicumference of the earth,where a curvature of the horizon is appearent?

OR---What's the max.length of cord,drawn

on the cicumference of the earth,where

length of the cord appears same as arc?

Follow up 2nd question---At what minimum

height above earth the curvature is noticable?