真円を作成する方法

//中心点座標
double X = ; //UTM座標系のX座標値
double Y = ; //UTM座標系のY座標値
double radius = 10500; //半径

//中心点 Point 作成
IPoint pPCenter = new PointClass();
pPCenter.PutCoors(X,Y);

//円周接点 Point 作成
IPoint pFromTo As IPoint = new PointClass();
pFromTo.PutCoords(X + radius, Y);

//円セグメントの作成
ICircularArc pCircularArc = new CircularArcClass();
pCircularArc.PutCoords(pPCenter, pPFromTo, pPFromTo, esriArcOrientation.esriArcClockwise);

//ポリゴンの作成
ISegmentCollection pSegmentCollection = new PolygonClass();
pSegmentCollection.AddSegment((ISegment)pCircularArc);
Sub subCreateCircle()
    '中心
    Dim pPCenter As IPoint
    Set pPCenter = New Point
    pPCenter.PutCoords 0, 0
    
    '円周接点
    Dim pPFromTo As IPoint
    Set pPFromTo = New Point
    pPFromTo.PutCoords 10, 10
    
    '円ジオメトリの作成
    Dim pCircularArc As ICircularArc
    Set pCircularArc = New CircularArc
    pCircularArc.PutCoords pPCenter, pPFromTo, pPFromTo, esriArcClockwise

End Sub