From: Gavin Sinclair <gsinclair@...>
Date: 2008-04-22T10:15:07+09:00
Subject: Re: Triangle Area (#160)

On Apr 20, 2:39 am, Matthew Moss <matthew.m...@gmail.com> wrote:
>
> Quiz #160
> Triangle Area
>
> Start with the following code for a Triangle class:
>
>     require 'matrix'
>
>     RANDOM_PT = lambda { Vector[rand(101)-50, rand(101)-50] }
>
>     class Triangle
>         def initialize(a, b, c)
>                 @a, @b, @c = a, b, c
>         end
>
>         def Triangle.random(foo = RANDOM_PT)
>                 Triangle.new(foo.call, foo.call, foo.call)
>         end
>
>         def [](i)
>                 [@a, @b, @c][i]
>         end
>
>         def area
>                 # Fill in this stub.
>         end
>
>         def inspect
>                 "Triangle[#{@a}, #{@b}, #{@c}]"
>         end
>         alias to_s inspect
>     end
>
> Your task this week is to write the code for the `area` method.
>

A method that hasn't been mentioned so far is "Heron's formula":

  Area = sqrt( s(s-a)(s-b)(s-c) )

    where a, b, c   are the lengths of the sides
      and 2s = a + b + c

If someone wants to implement that, I'd be keen to see what the code
looks like.

Cheers,
Gavin