google maps api pintar un circulo

var myLatlng = {lat: 38.35, lng: -0.49};

   var cityCircle = new google.maps.Circle({
      strokeColor: '#FF0000',
      strokeOpacity: 0.1,
      strokeWeight: 1,
      fillColor: '#FF0000',
      fillOpacity: 0.35,
      map: map,
      center: myLatlng,
      radius: 4000
    });


// radius se expresa en metros




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