drawing a line inside a circle
 

helo

I am drawing an orchestra seating plan. For this, I have a half circle. I need to draw lines in it to divide it in sexctions. Then I should get little textboxes in, the same as in the whole figure. How do I do tat or is there maybe a pie diagram available?

If you're using OmniGraffle 5.1 or later, there are arc and wedge shapes where you can drag the corners about to increase the angle, etc.

They're available from the Lines and Shape Inspector (where you would change an existing shape to the arc or wedge), and also in the Shapes stencil.

Hope that helps,