Find two numbers such that the mean proportional between them is 14 and third proportional to them is 112.
Find two numbers such that the mean proportional between them is 14 and third proportional to them is 112.

Let  the required numbers be a and b.

Given, 14 is the mean proportional between a and b.

\[\begin{array}{*{35}{l}}

a:\text{ }14\text{ }=\text{ }14:\text{ }b  \\

ab\text{ }=\text{ }196  \\

a\text{ }=\text{ }196/b\text{ }\ldots .\text{ }\left( 1 \right)  \\

\end{array}\]

Also, given, third proportional to a and b is 112.

\[\begin{array}{*{35}{l}}

a:\text{ }b\text{ }=\text{ }b:\text{ }112  \\

{{b}^{2}}~=\text{ }112a\text{ }\ldots .\text{ }\left( 2 \right)  \\

\end{array}\]

Using (1), we have:

\[\begin{array}{*{35}{l}}

{{b}^{2}}~=\text{ }112\text{ }\times \text{ }\left( 196/b \right)  \\

{{b}^{3}}~=\text{ }{{14}^{3}}~x\text{ }{{2}^{3}}  \\

b\text{ }=\text{ }28  \\

\end{array}\]

From (1),

a = 196/ 28 = 7

Therefore, the two numbers are 7 and 28.