Jump to content


Welcome to BrainDen.com - Brain Teasers Forum

Welcome to BrainDen.com - Brain Teasers Forum. Like most online communities you must register to post in our community, but don't worry this is a simple free process. To be a part of BrainDen Forums you may create a new account or sign in if you already have an account.
As a member you could start new topics, reply to others, subscribe to topics/forums to get automatic updates, get your own profile and make new friends.

Of course, you can also enjoy our collection of amazing optical illusions and cool math games.

If you like our site, you may support us by simply clicking Google "+1" or Facebook "Like" buttons at the top.
If you have a website, we would appreciate a little link to BrainDen.

Thanks and enjoy the Den :-)
Guest Message by DevFuse
 

unakade

Member Since 04 Apr 2013
Offline Last Active May 17 2013 05:54 PM
-----

Posts I've Made

In Topic: A miraculous voyage

17 May 2013 - 05:53 PM

But, how can it be a tetrahedron? The cities are just 5 miles away. Any 4 points on the surface of the earth which are also the vertices of a tetrahedron must be at a distance of 1.63 times the radius of the earth (which is about 6500 miles!!!).


In Topic: Out of respect to Bonanova--Fibonacci

04 April 2013 - 04:06 PM

Spoiler for

I am not quite sure about this because I did not find numbers a and b which give 216. Also, on wikipedia (http://en.wikipedia.org/wiki/Congruum), a list of first few congrua is given which does not contain 216. So, maybe 216 cannot be represented in this way. I did not find any other flaw in your argument.