im supposed to find the volume of the solid that results when the region enclosed by y = x^(1/2), y = 0 and x = 9. the region is revolved about the y = 3 line?

well my intergral that i got for this problem is.

V = pi*(the intergral of) (9 - y^(2))^(2) can someone tell me if the set up is right? basically i took the length of the strip to be my radius and then squared it times pi? thanks in advance...