How to replace red shap on google map with circle googlemap

Question

How to use circle on googlemap to location have latitude and longtude ?

I work on angular 7 

I use red shap on googlemap have latitude and longtude on component 

 i need only to make circle on map to the point have latitude and longtude

but i dont need to use red mark on map as following :

 

i need to replace it with circle 

so how to do that please ?

import { Component, AfterViewInit, ViewChild, ElementRef } from '@angular/core';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent implements AfterViewInit {
  title = 'angular-gmap';
  @ViewChild('mapContainer', { static: false }) gmap: ElementRef;
  map: google.maps.Map;

 lat = 40.73061;
 lng = -73.935242;

  coordinates = new google.maps.LatLng(this.lat, this.lng);

  mapOptions: google.maps.MapOptions = {
    center: this.coordinates,
    zoom: 8
  };

  marker = new google.maps.Marker({
    position: this.coordinates,
    map: this.map,
    title: 'Hello World!'
  });
  ngOnInit() {

    console.log("Hi man");
   // this.mapInitializer();
  }
  ngAfterViewInit() {
    console.log("Hi women");
    this.mapInitializer();
  }

  mapInitializer() {
    this.map = new google.maps.Map(this.gmap.nativeElement, this.mapOptions);
    this.marker.setMap(this.map);
  }
}

as sample above i need to use circle on  point

 

lat = 40.73061;

lng = -73.935242;

 

without using marker 

so what i change on code to do that?