Google Maps Java API - How to assign latitude and longitude to variable outside of Drawing Manager function

I'm attempting to pass the latitude and longitude to the global variables "lat" and "lng" in order to use them in an AJAX get request. How do I us the variables outside of the drawing manager function? As of now, when I attempt to use the variables "lat", "lng", and "radius" they are undefined.

var lat;
var lng;
var radius;
var circle;

function initialize() {

  var mapOptions = {
    center: new google.maps.LatLng(47.3850000, 39.2430556),
    zoom: 6
  };

  var map = new google.maps.Map(document.getElementById('map-canvas'),
    mapOptions);

  var drawingManager = new google.maps.drawing.DrawingManager({
    drawingMode: google.maps.drawing.OverlayType.MARKER,
    drawingControl: true,
    drawingControlOptions: {
      position: google.maps.ControlPosition.TOP_CENTER,
      drawingModes: [
        google.maps.drawing.OverlayType.CIRCLE,
      ]
    },

    circleOptions: {
      fillColor: '#017ad4',
      fillOpacity: .35,
      strokeOpacity: .80,
      strokeColor: '#02528d',
      strokeWeight: 2,
      clickable: false,
      editable: false,
      zIndex: 1
    }
  });

circles = new Array();


                    drawingManager.setMap(map);

                    google.maps.event.addListener(drawingManager, 'circlecomplete', function(circle) {
                        //exit the circle drawing mode
                        drawingManager.setDrawingMode(null);

                        //add the latest circle to the circles array
                        circles.push(circle);
                        //pop the previous drawn circle 
                        circles.reverse();

                        //pop the previous circle and set its map handle to null, so that only last drawn circle is shown
                        while(circles[1])
                        {
                            circles.pop().setMap(null);
                        }
            //get lat, long, and radius
            var lat = circle.getCenter().lat();
            var lng = circle.getCenter().lng();
            var radius = circle.getRadius();

            //test
            console.log("latitude: " + lat );
            console.log("longitude: " + lng);
            console.log("radius: " + radius);
        }); 
                } 

google.maps.event.addDomListener(window, 'load', initialize);