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Topic: Perpendicular Lines
Replies: 3   Last Post: Jan 2, 2013 11:09 PM

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 Guy Brandenburg Posts: 83 Registered: 1/30/05
Re: Perpendicular Lines
Posted: Jan 2, 2013 10:00 PM
 att1.html (3.5 K)

I would use the fact that with a circle, tangent lines are perpendicular to radii. Find lines tangent to a circle at such-and-such a point on the circle in the plane...

Guy Brandenburg, Washington, DC
http://gfbrandenburg.wordpress.com/
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________________________________
From: Fred Siegeltuch <notesforfred@yahoo.com>
To: "mathedcc@mathforum.org" <mathedcc@mathforum.org>
Sent: Wednesday, January 2, 2013 5:47 PM
Subject: Perpendicular Lines

Hi all,

I've seen tons of examples of math modeling where parallel lines arise and have a natural interpretation but I could use help in finding ones where the product of the slopes equals -1 is useful in modeling other than in doing bare geometry problems algebraically. I'd appreciate an example where this fact was used in such a way that covering this material didn't seem tangential (please forgive the pun) to a modeling perspective for algebra. I could try to embellish a problem that tries to find the tangent line to a circle or circular cylinder with a specific given radius but as of now I'm trying to do better. Ideally this should be no higher than the intermediate algebra level.

Thanks,

Fred Siegeltuch
City Colleges of Chicago

Date Subject Author
1/2/13 Fred Siegeltuch
1/2/13 Alain Schremmer
1/2/13 Guy Brandenburg
1/2/13 Lynne Ipina