Question

Find the value of x so that the given four numbers are in proportion:​
(v) $9,12,x\text{and}8$.

Answer 1

Since the numbers $9,12,x,\text{and}8$ are in proportion then ,

$\Rightarrow$ $9:12=x:8$

$\Rightarrow$ $\frac{9}{12}=\frac{x}{8}$

$\Rightarrow$ $9\times 8=x\times 12$

($\because$ $\text{Product of extremes = Product of means}$)


$\Rightarrow$ $x=\frac{9\times 8}{12}=\frac{3\times 3\times 4\times 2}{4\times 3}=3\times 2$

$\therefore$ $x=6$

Hence, the value of $x$ $\text{is}$ $6$