Question

if 8 x 18 are in proportion then find the value of x

Answer 1

8x=18
8=18/8=2.25.......

Answer 2

8:x::x:18
product of extreme =product of means
$8 \times 18 = x \times x \\ 144 = x {}^{2} \\ \sqrt{144 } = x \\ 12 = x$