Question

Find the value of $x$ in proportion 1.2 : 3.9 :: 2 : $x$
(A) 5.6
(B) 2.34
(C) 6.5
(D) 5.8
$\left[1\right]$

Answer 1

Given 1.2 : 3.9 :: 2 : $x$ are in proportion

Hence product of extremes = product of means

$1.2\times x=3.9\times 2$

$x=\frac{3.9\times 2}{1.2}$

$x=6.5$