On Sun, 20 Jan 2008 16:12:29 +0000, James Farrar
wrote:

snipped

Is it an annular sector?

Paul S


I thought annulus but I could be wrong

An annulus is a complete ring between two concentric circles.
http://en.wikipedia.org/wiki/Annulus_%28mathematics%29


Sorry - you're right. It's a long time since I did any geometry

Martin