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I bet this isn't our Frank Reed!

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Fred Hebard

On Dec 31, 2013, at 3:18 PM, Jackson McDonald wrote:

> Yep, that's me.  
> 
> 
> From: FrankReed{at}HistoricalAtlas.com
> To: jacksonmcdonald---.com
> Date: Tue, 31 Dec 2013 11:57:56 -0800
> Subject: [NavList] Re: Angular inclination of an interstate highway
> 
> Jackson McDonald, you wrote:
> "I'm neither an engineer nor a math whiz"
> In this case, actually, you may be in safer waters BECAUSE you do not have 
as much math background. This issue of dealing with small angles is one where 
a certain amount of mathematical background can get a person in trouble. 
Everyone that I have met who has good competence in trigonometry immediately 
wants to jump for the trig functions when they encounter a puzzle like this. 
This works... much as you can break eggs with a sledgehammer. Very effective. 
But over-kill and... messy! For small angles, we need to remember that angles 
ARE ratios --expressable as "percentages" as in those road signs or as plain 
numbers which is when they're often called angles in "radians" (this is true 
for any angle, but for small angles it's more important in practical terms). 
And we convert those ratios to minutes arc by multiplying by that magic 
number, 3438.
> And if you can do it in your head, then you can entertain yourself while 
driving! Whenever I am driving cross-country, when I encounter one of these 
grade signs giving the inclination in percentage, I work out the angle in my 
head to keep myself a little busy. 
> -FER
> PS: This must be you: http://en.wikipedia.org/wiki/Jackson_McDonald. 
Fascinating! ? ???? ?????? ???????? ??-??????.
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