http://qs1969.pair.com?node_id=199435

in reply to Re: Perl Humor

Surely a metric protractor would measure angles in radians. Sounds like someone fobbed you off with an imperial one because they didn't have the right one in stock :)

--
<http://www.dave.org.uk>

"The first rule of Perl club is you do not talk about Perl club."
-- Chip Salzenberg

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Re: Re: Re: Perl Humor
by BrowserUk (Patriarch) on Sep 20, 2002 at 15:46 UTC

Actually, years later I did encounter what might be term as a non-imperial (though not metric) protractor. It was marked up in grads (400 grads = 360 degrees).

I've never found a good explaination of when or where grads are useful as opposed to degrees or radians. They do show up on all three of my scientific calculators and even in the calculator on Windows in scientific mode.

I just found this which appears blames the grad on the (former) British Imperial Army, so maybe they are imperial and degrees should rightly be called metric.

Cor! Like yer ring! ... HALO dammit! ... 'Ave it yer way! Hal-lo, Mister la-de-da. ... Like yer ring!

I don't remember the details, but IIRC grads are used in range finding. Something along the lines of:

• you know the tank (boom boom) is 20 feet long.
• in my binoculars (with a grad scale on the inside) the tank spans 10 grads.
• the tank is (20/10)x100 feet away.

I either read this in some Army field manual or maybe my father tried to explain it to me.

No, no, it are "mils" you are thinking about. 1 mil is the arc of one meter seen at a distance of 1 km. There are about 6400 mils in a full circle.

CountZero

"If you have four groups working on a compiler, you'll get a 4-pass compiler." - Conway's Law

Well, gradians would be the "metric" version of degrees since in those units a right angle has 100 gradians, which fits better in the metric system. For whatever reason they are not. Gradians are used in geodesics, though.