Question

find the fourth proportional to the numbers 8, 36, 6

Answer 1

Let fourth proportion be x
Now
it means that
$\frac{8}{36} = \frac{6}{x} \\ x = \frac{36 \times 6}{8} \\ x = 27$
Hence fourth proportion is 27

Answer 2

The answer to this question is

Let the fourth proportion be x.
8:36::6:x
product of extreme =product of means
8×x=36×6
x=36×6/8
x=27