I.5.25 Volume of a Solid

Condition: Find the volume of the body limited by surfaces: \ [\ begin {array} {l} s_ {1}: x^{2}+y^{2} = z {2}, \ quad S_ {2}: x^{2}+y^{2}+z^{2} = r^{2}, \\ s_ {3}: y = 0, \ quad (y \ geq 0). \ end {Array} \]