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[TowerTalk] Elementary question - trig formula

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Subject: [TowerTalk] Elementary question - trig formula
From: clewis@ro.com (Chuck Lewis)
Date: Thu, 25 Jun 1998 16:14:43 -0500
Yep. Similar triangles...it's just a simple proportion...no trig needed.

B/(C+D) = ?/C     or, 

? = C x B/(C+D)

Example: If you have a 100' tower (C+D), and the guys are out 60' (B),

the distance out from the tower (?) at 50 feet DOWN (C) is

50' x 60'/100'  =  30'

Makes sense, huh? Just make sure you use the distance from the top down,
not the height of the (?). (Or redo the equation)

Chuck, N4NM

Pete Smith wrote:
> 
> At the risk of getting into the dumb question territory:
> 
> If you know how far from the base of your tower your guys attach (on flat
> ground), and you know how high they attach to the tower, then you should be
> able readily to calculate how much turning radius inside the guys would
> exist at any given height on the tower.  Obviously, this would be useful
> for assessing a potential stack design.
>                                                  I
>                                                 /I
>                                         / I
>                                        /  I C
>                                       /   I
>                                      /----I
>                                     /  ?  I
>                                    /      I D
>                                   /       I
>                             -----/----B---I---------
> 
> That is, if you know the lengths of B and C+D, then you ought to be able to
> figure out what "?" is for any length of C.
> 
> Unfortunately, I've forgotten virtually all the plane geometry and trig
> formulas I ever learned, and I didn't keep any high school math books.  I
> think the two triangles involved are called "similar triangles," but that's
> as far as my memory goes.  Can anyone tell me offhand what the right
> formula is for this?  Once I have the fomula I can do the calculations, but
> what to calculate?
> 
> Thanks!
> 
> 73,  Pete Smith N4ZR
> In wild, wonderful, fairly rare WEST Virginia
> 
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