All about flooble | fun stuff | Get a free chatterbox | Free JavaScript | Avatars    
perplexus dot info

Home > Shapes
Out for a walk (Posted on 2002-05-29) Difficulty: 3 of 5
There are some points on Earth for which the following is true:

Starting from one of these points, you can walk 1 km South, then 1 km East, then 1 km North, and you will wind up back where you started from.

One such point is the North Pole. Where are others?

See The Solution Submitted by Half-Mad    
Rating: 4.0833 (12 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
Some Thoughts re: TomM's answer in mathmatical terms | Comment 7 of 10 |
(In reply to TomM's answer in mathmatical terms by Zach Bolinger)

TomM describes the set of correct answers, but his math is slightly off. Since we're dealing with the surface of a sphere here, a circle with radius n does not have a circumference of 2*pi*n, but slightly less.

The earth has a circumference of 24,000 NM (nautical miles). As an extere case, consider the circle ceneterd on the south pole with a radius of 6,000 NM. (This circle is the equator.) Its circumference is 24,000 NM, a scant 4 times its radius, not 6.28 times its radius.

Admittedly, with the 160 meter and smaller circles contemplated, the inaccurracy is negligible. Negligible, but not zero.
  Posted by Jim Lyon on 2002-08-07 10:56:08

Please log in:
Login:
Password:
Remember me:
Sign up! | Forgot password


Search:
Search body:
Forums (1)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (10)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox:
Copyright © 2002 - 2024 by Animus Pactum Consulting. All rights reserved. Privacy Information