Mimic "pathfinder" with AS3?

I would like to create a half circle. Is there any way to do this using mc.graphics? I know that, say, I can draw a circle, and then draw another circle in the middle of that one, and the second will effectively cut out area from the first, in much the same way as Adobe Illustrator’s “pathfinder” function.

I tried making a half circle in a similar fashion, by first drawing a circle, then drawing a rectangle located such that it cuts the circle in half. The result is a half circle PLUS a rectangle with a half circle cut out of it.

Is it possible to use this technique in some other way to get JUST the half circle?