From: Eric Hu <eric@...>
Date: 2011-07-06T04:30:53+09:00
Subject: Re: Ruby Koan Exception Testing Question

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The pencil test is great, and now you understand the reasoning to learn the
generalization, the triangle inequality:

http://en.wikipedia.org/wiki/Triangle_inequality

Since 1 + 1 < 3, you know that this can't be a valid triangle.  Likewise, 2
+ 2 = 4, which is still not good enough.  There are exceptions to this rule,
but those exceptions are in non-Euclidean, non-spherical coordinate
systems.  You're probably not going to encounter triangles in such a
coordinate system unless you're working in advanced math/physics.




TLDR: Any triangle with sides A, B and C must satisfy this property

A + B > C  (you can rearrange any of the letters and this should be true)


On Sun, Jul 3, 2011 at 11:13 AM, comcast.net Leigh Daniels <lcdpublic@>wrote:

> I love the pencil!
>
> Thanks, Bill.
>
> **Leigh
>
> >> Am I missing something subtle? Or something obvious?
> >>
> >> **Leigh
> >
> >>      assert_equal :isosceles, triangle(1, 1, 3) # these two are from
> >>      assert_equal :isosceles, triangle(2, 4, 2) #
> >
> >Are these really triangles? Try to draw them.
> >
> >-- Bill
>
>
>
>

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