Using geometry calculate the volume of the solid under z sq

Using geometry, calculate the volume of the solid under z = sqrt(9-x^2-y^2) and over the circular disk x^2+y^2<=9

Solution

first one is equation of hemisphere above xy plane having radius 3

so volume of the solid over the circular disk x^2+y^2<=9 = volume of hemisphere of radius 3=2 pi r^3/3=56.53