Question

The value of $x$ for which the numbers $20,15,x,18$ are in proportion is

Answer 1

As we know that any four numbers $a,b,c$ and $d$ are said to be in proportion if and only if

$a:b::c:d$

$\frac{a}{b}=\frac{c}{d}$

Given $20,15,x,18$ are in proportion, therefore we have

$\frac{{\displaystyle 20}}{{\displaystyle 15}}=\frac{{\displaystyle x}}{{\displaystyle 18}}$

$\frac{{\displaystyle 4}}{{\displaystyle 3}}=\frac{{\displaystyle x}}{{\displaystyle 18}}$

$x=\frac{4\times 18}{3}$

$x=4\times 6$

$x=24$

Hence, the value of $x$ is $24$ when four numbers $20,15,x,18$ are in proportion.