### mphToKph

Convert miles/hour to kilometers/hour.

Multiply the constant of proportionality with the argument.

```js
const mphToKph = (mph) => 1.6093440006146922 * mph;
```

```js
mphToKph(10); //16.09344000614692
mphToKph(85.9); //138.24264965280207
```