Find the value of $x$ if 27:$x$ :: 63:84

The correct answer is 36

As 27:$x$ :: 63:84,
$\dfrac{27}{x}$ = $\dfrac{63}{84}$

⇒ $\dfrac{27}{x}$ = $\dfrac{3}{4}$

∴ $x$ = $\dfrac{27 × 4}{3}$ = 36

Hence $x$ = 36.