# Triangle Determine if a triangle is equilateral, isosceles, or scalene. An _equilateral_ triangle has all three sides the same length.
An _isosceles_ triangle has at least two sides the same length. (It is sometimes specified as having exactly two sides the same length, but for the purposes of this exercise we'll say at least two.)
A _scalene_ triangle has all sides of different lengths. ## Note For a shape to be a triangle at all, all sides have to be of length > 0, and the sum of the lengths of any two sides must be greater than or equal to the length of the third side. See [Triangle Inequality](https://en.wikipedia.org/wiki/Triangle_inequality). ## Dig Deeper The case where the sum of the lengths of two sides _equals_ that of the third is known as a _degenerate_ triangle - it has zero area and looks like a single line. Feel free to add your own code/tests to check for degenerate triangles. ## Elm Installation Refer to the [Exercism help page](http://exercism.io/languages/elm) for Elm installation and learning resources. ## Writing the Code The first time you start an exercise, you'll need to ensure you have the appropriate dependencies installed. ```bash $ npm install ``` Execute the tests with: ```bash $ npm test ``` Automatically run tests again when you save changes: ```bash $ npm run watch ``` As you work your way through the test suite, be sure to remove the `skip <|` calls from each test until you get them all passing! ## Source The Ruby Koans triangle project, parts 1 & 2 [http://rubykoans.com](http://rubykoans.com) ## Submitting Incomplete Solutions It's possible to submit an incomplete solution so you can see how others have completed the exercise.