Question

the geometric mean of 5 and 4 is:
$2\sqrt{5}$
10.
20.
none of the choices are correct.

Explanation:

Step1: Recall geometric mean formula

The geometric mean of two numbers \(a\) and \(b\) is \(\sqrt{ab}\).

Step2: Substitute \(a = 5\) and \(b = 4\)

Calculate \(\sqrt{5\times4}=\sqrt{20}\). Simplify \(\sqrt{20}\) as \(\sqrt{4\times5}=2\sqrt{5}\).

Answer:

\(2\sqrt{5}\) (the first option, with the dotted - boxed circle next to it)