Re: Compute Angles of a Right Triangle

Unless my trig fails me, something like this should work. I converted to degrees, but you could use Math::Trig::Degrees, too.

use strict;
use Math::Trig;
my @lengths = (3,4,5);
my @slengths = sort {$a <=> $b} @lengths;
my $a1 = atan($slengths[1]/$slengths[0]) * 180/3.141592653589;
my $a2 = 90 - $a1;
print "Angles are $a1, $a2\n";
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HTH, --traveler

Comment on Re: Compute Angles of a Right Triangle Download Code

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Re: Re: Compute Angles of a Right Triangle by ysth (Canon) on Dec 11, 2003 at 02:54 UTC
That's a nice solution. To comment on it a little, the sort finds the two shortest sides (so the hypotenuse is ignored). atan computes the the arctangent. Math::Trig is bundled with perl, but if you wanted to use a builtin, you could use atan2 instead, passing the two sides as separate arguments. That isn't as acurate a value of pi as possible. 3.14159265359 is closer (since the digits following 89 are 7932). You can use 4*atan2(1,1) to get a value with accuracy commensurate with your perl's floating point accuracy.	[reply]
Re: Re: Re: Compute Angles of a Right Triangle by duff (Parson) on Dec 11, 2003 at 03:43 UTC
You can use 4atan2(1,1) to get ... [pi]* Or, since `atan2()` is properly ranged from -pi to pi, you can use `atan2(0,-1)` and forego the multiplication PerlJam	[reply] [d/l] [select]