Get an element from JSON array in Laravel 5.3

I need to get latitude and longitude from this array:

AddressCollection {#237 ▼
-addresses: array:1 [▼
0 => Address {#232 ▼
  -coordinates: Coordinates {#233 ▼
    -latitude: 55.923431
    -longitude: 23.3490609
  }
  -bounds: Bounds {#234 ▶}
  -streetNumber: "18"
  -streetName: "Vilniaus gatvė"
  -subLocality: null
  -locality: "Šiauliai"
  -postalCode: "76258"
  -adminLevels: AdminLevelCollection {#235 ▶}
  -country: Country {#236 ▶}
  -timezone: null
}
]
}

Code in my controller:

 $posts = Post::latest()->get();  
     Mapper::location('Lietuva')->map(['zoom' => 7, 'scrollWheelZoom'=>false, 'marker'=>false]); //A map is displayed in the index page
    foreach($posts as $post){

        $city = $post->city;
        $address = $post->address;

        $mark = app('geocoder')->geocode($city . $address)->get();

        dd($mark);
        //
        //THIS IS WHERE I NEED THOSE COODINATES
        //
        //For example $lat = $mark->coordinates.......

        //Mapper::marker($lat, $long); Make a marker for every address in the DB
    }
 return view('posts.index', compact('posts'));

Not sure if this will generate markers for my map, but i still have no idea how to get specific information from JSON array. Thank you in advance

via Dziubutkus