Question

Find the mean proportional between the following:

$2$ and $18$

Answer 1

Let $x$ be the mean proportion. Then $2,x,\&18$ are in continued proportion.

$b^2=ac$ $\left[b=x,a=2,\&c=18\right]$

$x^2=2\times 18$

$x=\sqrt{36}$

$x=6$

So, $6$ is the mean proportion between $2$ and $18.$