Complete the ratio table 3__ 9 12 15

The common ratio in this table is 3.

To complete the table, multiply each number by the common ratio:
3 × 3 = 9
9 × 3 = 27
12 × 3 = 36
15 × 3 = 45

So the completed ratio table is:
3 9 12 15
9 27 36 45