a circle has a sector with the area 9pi and central angle of 17/9pi radians
So what are we solving for here? I'm assuming that the circle has the area of \(9\pi\) . If so, then we should convert radians to degrees, which gives us 340 degrees. So a 20 degree sector. I think that the sector that you're talking about is the one with 340 degrees. To find the ratio of the sector to circle, we get \(\frac {340}{360} = \frac {17}{18}\).So the sector has area \(\frac {17\cdot 9\pi}{18} = \frac {153\pi}{18}\).
Hope this helps!