Respuesta :

Step-by-step explanation:

when we get the common ratio that  must be equal

r=16/64=4/16=1/4=1/4   equal

So it is geometric

By using this equation:

a(n)=a(1)*r^(n-1)

and we have a(1)=64 , r=1/4  

Explicit rule: a(n)=64*(1/4)^(n-1)

hope this helps