How to draw an ARC using iTextSharp

Hi there,
I have been producing my own pdf documents using VB.NET and iTextSharp.  So far it has all been going ok but I can't seem to be able to draw an arc.  No matter what I try it always seems to end up being a straight line.

Can someone please help me.

I have tried many different combinations of values.  The line that is generated moves but is still a straight line.

I'm trying to draw half of an ellipse.

Dim FileStream as new IO.FileStream("C:\test.pdf", IO.FileMode.Create)
Dim doc As new Document
Dim writer As iTextSharp.text.pdf.PdfWriter = pdf.PdfWriter.GetInstance(doc, FileStream)
Dim cb As PdfContentByte = writer.DirectContent

doc.SetPageSize(PageSize.A4)

cb.Arc(100, 100, 100, 200, 135, 180)
cb.Stroke()

FileStream.Close()
FileStream.Dispose()

Select allOpen in new window