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x = 2 sqrt(y), x = 0, y = 9; about the y-axis

I have this graphed and everything so I'm not sure there's a need to worry about that.

Setup (integrating with respect to y):

Outer radius = x = 2 sqrt(y). Inner radius = x = 0. Bounded by y = 9 and 0.

9

∫π[2 sqrt(y)]^2 dy

0

Which is equivalent to:

_______9

(2πy^2)| = 36π

_______0

However, my book says the answer is 162π. What am I doing wrong?