Answer :
[tex]the\ geometric\ mean= \sqrt{5\cdot125} = \sqrt{625} = \sqrt{25^2}= 25[/tex]
[tex]geometric \ mean \ of \ two \ numbers \ a \ and \ b \ is :\ \sqrt{a \cdot b} \\ \\a=5 , \ b = 125 \\ \\ \sqrt{5 \cdot 125}=\sqrt{625}=\sqrt{25 \cdot 25}=25[/tex]