A definition of a common ration Is the number multiplied must be the same for each term in the sequence. The common ratio is the amount between each number in a geometric sequence. To determine the common ration you can just divide each number from the number preceding it in the sequence. Here is an example I found of a common ration to further help you
2,4,8,16
16/8=2 you would then continue to divide to ensure that the pattern is the same for each number
8/4=2
4/2=2 the ratio is the same for each one so the common ration would be 2 I hope this helps could I please get a brainliest :)