c# Using GMap How to Map Circles with a Set Radius as Markers

Question

I have added a Gmap to a winform, but I would like to add markers as circles that have a set radius such as 100 meters. I have searched online but can't see anything that supports this. What I have done so far below is very limited, but I'm not sure how to progress this at all.

private void btnLoadIntoMap_Click(object sender, EventArgs e)
{
    map.MapProvider = GMapProviders.GoogleMap;
    double lat = Convert.ToDouble(txtLat.Text);
    double lng = Convert.ToDouble(txtLng.Text);
    map.Position = new GMap.NET.PointLatLng(lat, lng);

    PointLatLng point = new GMap.NET.PointLatLng(lat, lng);
    GMarkerGoogle marker = new GMarkerGoogle(point, GMarkerGoogleType.blue_dot);

    GMapOverlay markers = new GMapOverlay("markers");
    markers.Markers.Add(marker);

    map.Overlays.Add(markers);
}