Given
4
18
Procedure
The mean proportional, or geometric mean, of two positive The mean proportional, or geometric mean, of two positive
[tex]\frac{a}{x}=\frac{x}{b}[/tex]When solving
[tex]\begin{gathered} x=\sqrt[]{a\cdot b} \\ x=\sqrt[]{4\cdot81} \\ x=\sqrt[]{324} \\ x=18 \end{gathered}[/tex]The answer would be 18