How do I find the common ratio of this geometric sequence 1,4,16,64?

Answer 1

To find the common ratio of a series, you just divide a term in the series by the one that comes before it. And generally, just to double check your work and to make sure you are indeed dealing with a geometric series, you try another pair of successive terms to make sure you get the same ratio. So in this series we can see that 4/1=4, and 16/4=4, and 64/16=4. So the common ratio is 4.