，关于silverlight用path或者GeometryGroup的有关问题

求助，关于silverlight用path或者GeometryGroup的问题
我用GeometryGroup组合了一些自己画的图像，我想要的结果是两个部分构成一个扇形。代码如下：
<Path Stroke="Blue" StrokeThickness="3" Fill="Blue" MouseLeftButtonDown="panElement_MouseLeftButtonDown" Name="PanUp">
                <Path.Data>
                    <GeometryGroup >
                        <LineGeometry StartPoint="40,40" EndPoint="75,75" />
                        <LineGeometry StartPoint="75,75" EndPoint="110,40" />
                        <LineGeometry StartPoint="110,40" EndPoint="40,40"/>
                        <PathGeometry >
                            <PathGeometry.Figures>
                                <PathFigure StartPoint="110,40">
                                    <PathFigure.Segments>
                                        <ArcSegment Size="50,50" RotationAngle="45" IsLargeArc="False"  SweepDirection="Counterclockwise" Point="40,40"/>
                                    </PathFigure.Segments>
                                </PathFigure>
                            </PathGeometry.Figures>
                        </PathGeometry>
                    </GeometryGroup>
                </Path.Data>
            </Path>


出现的效果只有上面的那部分，下面的那个相当于三角形的不填充，该怎么画呢？
三条边组合的，两条线段加一段弧组合的。
------解决方案--------------------

       <Path Stroke="Blue" StrokeThickness="1"  Fill="Blue"  Name="PanUp">

            <Path.Data>

                <GeometryGroup FillRule="Nonzero">

                    <!--<LineGeometry StartPoint="40,40" EndPoint="75,75" />

                    <LineGeometry StartPoint="75,75" EndPoint="110,40" />

                    <LineGeometry StartPoint="110,40" EndPoint="40,40"/>-->

                    <PathGeometry >

                        <PathGeometry.Figures >

                            <PathFigure StartPoint="40,40" IsFilled="True"  >

                                <PathFigure.Segments >

                                    <LineSegment Point="75,75" ></LineSegment>

                                    <LineSegment Point="110,40"></LineSegment>