Forwarded from SBG ...
-------
Date: Mon, 30 Aug 2010 12:08:08 -0700
Subject: Re: [math-fun] left vs. right
From: "Stephen B. Gray" <stevebg(a)roadrunner.com>
Here's an exercise in 3D visualization. Given a point P, is it possible to
construct FIVE rays coming out from P such that every ray makes an obtuse
angle (>90 degrees) with every other one? (That's 10 angles that must be
obtuse.) Explain your answer.
Steve Gray
On 8/30/2010 11:44 AM, James Buddenhagen wrote:
> Interesting. I always assumed that people who had trouble with maps,
> cardinal directions, etc. were not math people. Perhaps it is because I was
> around maps since a child that I have always puzzled that some people have
> trouble with them. When heavy fog or overcast I get lost much easier than
> on clear sunny days, but I do not consciously think about the sun or
> shadows.
>
> Whereas visualizing geometric solids seems easy for me, this I assume is
> learned. Nonetheless, I am almost always confused by illustrations of how
> to insert cards in ATM machines, and have even resorted to first trying the
> opposite of what I think it says, my wife never has this problem. Also, she
> finds ambiguous directions that others give about how to get somewhere
> unambiguous, while I am weighing the odds of what interpretation to give. I
> guess people are just different.
>
