Question

Find the value of 𝑥 in each of the following such that the given numbers are in proportion.

(ii) $45,135,90$ and $x$

Answer 1

Step : Calculate the value of $x$
Given numbers are $45,135,90$ and $x$.
If $45:135$ is equal to $90:x$ then they are in proportion.

$\therefore 45:135=90:x$
$\Rightarrow 45\times x=90\times 135$
($\therefore$ Product of extremes = product of means)
$\Rightarrow x=\frac{90\times 135}{45}=\frac{15\times 6\times 15\times 9}{15\times 3}$
$\Rightarrow x=\frac{6\times 3\times 5\times 9}{3}$
$\therefore x=270$
Hence, the value of $x$ is $270$.