#1**+2 **

Arithmetic....the common difference between terms is 10 - 1 = 9

So

1, 10, 19, 28

Geometric...the common ratio between terms = 2nd term / 1st term = 10 / 1 = 10

So....each successive term is 10 times the previous one

So

1, 10, 100, 1000

Neither

1, 10, 13, 15

We have no common difference or common rato

CPhill Apr 13, 2019