# Solution: Extension Methods

Solution for extension method challenge.

## We'll cover the following

# Solution: Extension Methods

In this lesson, you will explore the solution to the “Extension Methods” challenge.

## Solution #1

The first challenge is to implement the `convertMileToKm()`

extension method. This method converts the mile(s) to the kilometer(s). Since we know 1 mile is equivalent to 1.6 kilometers, we need to multiply the given mile with 1.6 to calculate the kilometer equivalent.

`this`

refers to the object the extension method is called upon. The object is passed implicitly.

```
double convertMileToKm() => this * 1.6;
```

## Solution #2

The second part of the challenge is to call `convertMileToKm()`

on the double `mile`

value and print its kilometers equivalent.

```
double kms = mile.convertMileToKm();
```

Try the code snippet below to evaluate the code altogether.

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