Drawing partial circle arc in 2D

Question

I'm trying to draw a partial circle arc in Visual Basic. (Example: 75% of an outer arc.)

I tried to do this both by adding in the Visual Power Packs and by using the below code but I can't seem to figure out how to hide a portion of the arc without either covering everything within the circle or disabling the circle altogether.

(The goal being that as the countdown timer ticks down, a portion of the circle disappears as the clock is counting down. So at 0:15, there's half the circle and the like.)

Is there a way to draw a 2D circle arc that doesn't involve using any sort of graphics engine?