Question

Find the fourth term of the proportion whose first, second and third terms are $18,27\text{and}32$ respectively.​

Answer 1

Let the fourth term be $x$.

Since the numbers $18,27,32\text{and}x$ are in proportion

$\Rightarrow$ $18:27=32:x$

$\Rightarrow$ $18\times x=32\times 27$

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


$\Rightarrow$ $x=\frac{32\times 27}{18}=\frac{16\times 2\times 9\times 3}{9\times 2}=48$

$\therefore$ $x=48$

Hence, the fourth term of the proportion is $48$.