Question

Are the following in proportion?

$12,36,18,25$

Answer 1

Given

$12,36,18,25$

It is written as $12:36::18\hspace{0.17em}:25$

First and last term is called extreme terms, that is $12$ and $25$ and $36$ and $18$ is called middle terms.

product of extreme terms = product of middle terms

$$\begin{gathered} 12\times 25=36\times 18 \\ 300\ne 648 \end{gathered}$$

Hence $12,36,18,25$ are not in proportion.