# Distance Special class for calculation of different types of distance. ### Euclidean ![euclidean](https://upload.wikimedia.org/math/8/4/9/849f040fd10bb86f7c85eb0bbe3566a4.png "Euclidean Distance") To calculate euclidean distance: ``` $a = [4, 6]; $b = [2, 5]; Distance::euclidean($a, $b); // return 2.2360679774998 ```