Triangle exercise in java on the triangle inequality

Hello,

On the triangle part, I saw double manipulation for adding values.
As we know, double is not precise and we need to use the BigDecimal in order to have an exact calculation.

Is it necessary in this exercise? Is it a good way to introduce the double vs BigDecimal ? As it is a medium exercise, it is perhaps good to add a unit test that will emphasize this problem?

I test with this unit test :
```
Triangle triangle = new Triangle(0.18, 0.16, 0.33999999999999999);
assertTrue(triangle.isScalene());
```
This test throw an exception with the current implementation in the code in .meta.