Hi Student!
In the question we are given two numbers and told to find the geometric mean of them. A normal mean would be just taking the average by multiplying them against each other and dividing by two. However, for geometric mean we multiply them against each other but put them inside of a square root.
[tex]mean = \sqrt{a*b}[/tex]
[tex]mean = \sqrt{40*30}[/tex]
[tex]mean = \sqrt{1200}[/tex]
[tex]mean = \sqrt{20^2*3}[/tex]
[tex]mean = 20\sqrt{3}[/tex]
Therefore, our geometric mean is [tex]34.64[/tex] or [tex]20\sqrt{3}[/tex].