(iii) \[1.5,\text{ }2.5,\text{ }4.5\]
Consider x as the fourth proportional to \[1.5,\text{ }2.5,\text{ }4.5\]
\[1.5:\text{ }2.5\text{ }::\text{ }4.5:\text{ }x\]
We can write it as
\[1.5\text{ }\times \text{ }x\text{ }=\text{ }2.5\text{ }\times \text{ }4.5\]
So we get
\[\begin{array}{*{35}{l}}
x\text{ }=\text{ }\left( 2.5\text{ }\times \text{ }4.5 \right)/\text{ }1.5 \\
x\text{ }=\text{ }7.5 \\
\end{array}\]
(iv) \[9.6\text{ }kg,\text{ }7.2\text{ }kg,\text{ }28.8\text{ }kg\]
Consider x as the fourth proportional to \[9.6\text{ }kg,\text{ }7.2\text{ }kg,\text{ }28.8\text{ }kg\]
\[9.6:\text{ }7.2\text{ }::\text{ }28.8:\text{ }x\]
We can write it as
\[9.6\text{ }\times \text{ }x\text{ }=\text{ }7.2\text{ }\times \text{ }28.8\]
So we get
\[\begin{array}{*{35}{l}}
x\text{ }=\text{ }\left( 7.2\text{ }\times \text{ }28.8 \right)/\text{ }9.6 \\
x\text{ }=\text{ }21.6 \\
\end{array}\]