Question

find the volume between x=sqrt(y^2+z^2) and x^2+y^2+z^2=9

Answer 1

http://www.examsolutions.net/maths-revision/syllabuses/OCR/period-1/C3/module.php scroll down to the bottom, you will see volumes of revolution
those videos may help you

Answer 2

1. graph those two surfaces
2. find the intersection plane.

Answer 3

3. use the definition double integral to find the volume.
\[V = \iint f(x,y) ds \]

Answer 4

4. try to look at the geometry of the problem ... and use 3. stepwise.