Respuesta :

Let a₁ , a₂ , a₃ , a₄ ,... .be a given sequence.
The common ratio of this sequence is the following:
 a₂/a₁ = a₃/a₂ = a₄/a₃ = r

Example: 5, 25, 125, 625, ...The common ration  is:
 25/5 = 125/25 = 625/125 = 5. So r=5 is the common ratio