Hi I'm having some trouble with this problem. I've been doing the problem the same exact way for the last couple problems but I cant seem to get the correct answer no matter how I look at it. I do it the same as the X way and this problem doesnt have the example so I'm kind of lost.
I plug in 9 and get 72pi. I'm sure I'm missing a step, would anyone care to share?
I do (8/9 pi *81)
which is
(.888888888889 pi * 81) which gives me a nice whole number 72pi but its not the correct answer... I know if you plug in 0 then it'll just be 0 so I have no clue! D: