### Home > CALC > Chapter 2 > Lesson 2.1.3 > Problem2-39

2-39.

Calculate the volume of the solid formed by rotating the flag bound by the $x$- and $y$-axes and $y = \sqrt { 9 - x ^ { 2 } }$, in the first quadrant, about the $y$-axis.

The area contained in the first quadrant is under a quarter-circle.

The flag will be rotated about the $y$-axis. This will result in the same volume as rotating about the $x$-axis.

The resultant 3D figure will be a half-sphere.