Forwarded from SBG ... ------- Date: Mon, 30 Aug 2010 12:08:08 -0700 Subject: Re: [math-fun] left vs. right From: "Stephen B. Gray" <stevebg@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.