Let R be the region enclosed by Y is equal to four times the square root of nine minus X and the axes in the first quadrant. And we can see that region R in gray right over here. Region R is the base of a solid. For each Y value, the cross section of the solid taken perpendicular to the Y axis is a rectangle whose base lies in R and whose height is Y. Express the volume of the solid with a definite integral. So pause this video and see if you can do that. All right, now let's do this together.