# Aptitude Question ID : 93621

If a : b = b : c, then $a^{4}:b^{4}$ is equal to:
[A]$b^{2}: ac$
[B]$ac : b^{2}$
[C]$c^{2}: a^{2}$
[D]$a^{2}: c^{2}$

$\mathbf{a^{2}: c^{2}}$
$\frac{a}{b} = \frac{b}{c}$
$=> b^{2} = ac$
$=> b^{4} = a^{2}c^{2}$
$\therefore \frac{a^{4}}{b^{4}} = \frac{a^{4}}{a^{2}c^{2}} = \frac{a^{2}}{c^{2}} = a^{2} : c^{2}$
Hence option [D] is the right answer.