Filtering based on calculation inside whereHas Eloquent Laravel

I am trying to filter jobs which have location distance less than certain limit as follows. Job and Location have many-many relation.

Job.php

class Job extends Model
{
 protected $table = 'jobs';
 protected $fillable = ['company_id', 'role_id', 'job_title'];

  public function location()
  {
        return $this->belongsToMany('App\Pincode', 'job_pincodes', 'job_id', 'location_id');
  }
}

Pincode.php

class Pincode extends Model
{
 protected $table = 'pincodes';

 protected $fillabe = ['location', 'pincode', 'state', 'district'];

 public function jobs()
 {
    return $this->belongsToMany('App\Job');
 }
}

The problem is that I don't know how to access each row of relationship inside whereHas. Please help.

 $user_lat = 28.7041;
 $user_long = 77.1025;
 $distance = 12;
 $result = Job::whereHas('location',function($query)
 use($user_lat,$user_long,$distance){
  // I don't know how to access location's column values to calculate distance
  $query->whereRaw('3959 * acos( cos( radians(?) ) * cos( radians(?) ) * cos( radians(?) - radians(?) ) + sin( radians(?) ) * sin(radians(?)) ) <=?', array($location->lati, $user_lat, $location->longi, $user_long, $location->lati,$user_lat, $distance));
   }

via Nitesh Verma