# How do you find the geometric mean between 81 and 4?

Jun 1, 2018

$18$

#### Explanation:

the geometric mean of two numbers$\text{ } a , b$

${G}_{m} = \sqrt{a b}$

we have

${G}_{m} = \sqrt{4 \times 81}$

$= 9 \times 2 = 18$

Jun 1, 2018

$G = \sqrt{81 \times 4} = \sqrt{{9}^{2} \times {2}^{2}} = 9 \times 2 = 18$

#### Explanation:

We know that,

Geometric Mean $G$ of two numbers $a \mathmr{and} b$ is :

$G = \sqrt{a b}$

Let, $a = 81 \mathmr{and} b = 4$

So,

$G = \sqrt{81 \times 4} = \sqrt{{9}^{2} \times {2}^{2}} = 9 \times 2 = 18$