Question

Find the fourth proportional of:​(v)$4$ hours $40$minutes, $1$hours $10$ minutes and $16$ hours.​

Answer 1

Let the fourth proportional be $x$
$\therefore$ $\frac{1}{3}:\frac{2}{5}=8.4:x$
[$\therefore$ Ratio of first two terms = Ratio of last two terms]
$\Rightarrow$ $\frac{1}{3}÷\frac{2}{5}=\frac{8.4}{x}$
$\Rightarrow$$\frac{5}{6}=\frac{8.4}{x}$
$\Rightarrow$ $x=\frac{6\times 8.4}{5}=\frac{50.4}{5}=10.08$
​​​​​​​Hence, the fourth proportion is $10.08$.