How do I add a radius line from the center of the circle to a point on the circle - arcgis-js-api

Question

The following code adds a circle of given radius to the graphics layer on an ArcGIS map. How can I add a line that joins center of the circle to any point on the circle to the graphics layer.
Basically the question is how do I calculate a point on the circle, draw a line that joins the center to the point on the circle and add it to the graphics layer.
performSearchPoint : function(e) {
var self = this;
var radius = $('#radius-distance').val();
if(radius > 0 && radius < 100000){
$('#besideMouse').removeClass('hide');
$('#besideMouse').show();
var loadingBMint = setInterval(this.loadingBM, 0);
var searchPointClick = OURAPP.App.Map.on("click",function(evt) {
loadingBMint = clearInterval(loadingBMint);
$('#besideMouse').hide();
var radius = $('#radius-distance').val();
var units = $("input:radio[name='unitsGroup']:checked").val();
if (units == "miles"){
units = "9035"; // if we use GeometryService
} else {
units = "9003"; // if we use GeometryService
}
//clear only search graphics
for ( var gr in OURAPP.App.Map.graphics.graphics) {
if(OURAPP.App.Map.graphics.graphics[gr].infoTemplate != null){
var template = OURAPP.App.Map.graphics.graphics[gr].infoTemplate;
if(template != "undefined" || template != null){
if(template.title.trim() == "Search Graphic"){
OURAPP.App.Map.graphics.remove(OURAPP.App.Map.graphics.graphics[gr]);
}
}}}
/*do buffer geometry for draw circle and use the circle geometry to get the features*/
var geoService = new OURAPP.esri.GeometryService("http://XXXX:YYYY/arcgis/rest/services/Utilities/Geometry/GeometryServer");
var params = new OURAPP.esri.BufferParameters();
params.geometries = [ evt.mapPoint ];
params.distances = [ radius ];
params.unit = units;
params.bufferSpatialReference = OURAPP.App.Map.spatialReference;
params.outSpatialReference = new OURAPP.esri.SpatialReference(4326);
var bufferPolygon = new OURAPP.esri.Polygon;
bufferPolygon.spatialReference = new OURAPP.esri.SpatialReference(4326);
geoService.buffer(params,function(geometries) {
var symbol = new OURAPP.esri.SimpleFillSymbol()
.setColor(null).outline.setColor("red");
dojo.forEach(geometries,function(geometry) {
geometry.spatialReference = new OURAPP.esri.SpatialReference(4326);
var graphic = new OURAPP.esri.Graphic(geometry,symbol);
// add name to identify the search graphics
var template = new OURAPP.esri.InfoTemplate(graphic.geometry);
template.setTitle("Search Graphic");
template.setContent("Map Query circle with Radius: " + radius);
graphic.setInfoTemplate(template);
OURAPP.App.Map.graphics.add(graphic);
bufferPolygon = geometry;
OURAPP.App.Map.setExtent(graphic.geometry.getExtent().expand(2));
});
self.searchType="Distance Search from point";
self.nameofplace=radius + " "+$("input:radio[name='unitsGroup']:checked").val();
self.showCount(bufferPolygon);
});
searchPointClick.remove();
});
}
},

Answer 1

I was able to draw a line and add it to the graphics layer using the following. The [-XX.XXXXXXXXXXXX,YY.YYYYYYYYYYY] is a random point on the map, Now only thing left is to find a point on a circle. So now the question becomes how to find a point which is X miles from a known point(Center of the circle) along the same latitude.
var lineSymbol = new OURAPP.esri.CartographicLineSymbol(
OURAPP.esri.CartographicLineSymbol.STYLE_SOLID,
new OURAPP.esri.Color([255,0,0]), 2,
OURAPP.esri.CartographicLineSymbol.CAP_SQUARE,
OURAPP.esri.CartographicLineSymbol.JOIN_MITER, 5
);
var lineGeometry = new OURAPP.esri.Polyline;
lineGeometry.spatialReference = new OURAPP.esri.SpatialReference(4326);
lineGeometry.addPath([[evt.mapPoint.getLongitude(),evt.mapPoint.getLatitude()], [-XX.XXXXXXXXXXXX,YY.YYYYYYYYYYY]])
var lineGraphic = new OURAPP.esri.Graphic(lineGeometry, lineSymbol);
OURAPP.App.Map.graphics.add(lineGraphic);

Answer 2

This is the best possible one i came up with and its working.
var lineSymbol = new OURAPP.esri.CartographicLineSymbol(
OURAPP.esri.CartographicLineSymbol.STYLE_SOLID,
new OURAPP.esri.Color([255,0,0]), 2,
OURAPP.esri.CartographicLineSymbol.CAP_SQUARE,
OURAPP.esri.CartographicLineSymbol.JOIN_MITER, 5
);
var radiusInMeters;
if (selectedUnit == "miles"){
radiusInMeters = radius*1609.34; //have to convert it to meters.
} else {
radiusInMeters = radius*0.3048; //have to convert it to meters.
}
// Calculate the new map point on the circle.
var radians = Math.PI/180;
var ltLong = OURAPP.esri.webMercatorUtils.xyToLngLat(evt.mapPoint.x + radiusInMeters*Math.cos(radians), evt.mapPoint.y + radiusInMeters*Math.sin(radians));
// Calculate the new map point on the circle.
var lineGeometry = new OURAPP.esri.Polyline;
lineGeometry.spatialReference = new OURAPP.esri.SpatialReference(4326);
lineGeometry.addPath([[evt.mapPoint.getLongitude(),evt.mapPoint.getLatitude()], ltLong]);
var lineGraphic = new OURAPP.esri.Graphic(lineGeometry, lineSymbol);