Question

Find the value of $x$ So that the given four numbers are in proportion: (ii) $x,4,15\text{and}30$.

Answer 1

Since the numbers $x,4,15\text{and}30$ are in proportion then ,

$\Rightarrow$ $x:4=15:30$

$\Rightarrow$ $\frac{x}{4}=\frac{15}{30}$

$\Rightarrow$ $x\times 30=15\times 4$

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

$\Rightarrow$ $x=\frac{60}{30}=2$

$\therefore$ $x=2$

Hence , the value of $x$ is $2$.