Answer: 3, 6, 9, 12
Explanation:
A geometric progression has a common ratio.
2,6, 18 and 54 has a common ratio of 3. When you multiply the first number by 3, you get the second number and the same thing applies to the third number.
1, 5, 25 and 125 has a common ratio of 5. When you multiply the first number by 5, you get the second number and the same thing applies to the third number.
4, 8, 16 and 32 has a common ratio of 2. When you multiply the first number by 2, you get the second number and the same thing applies to the third number.
3, 6, 9 and 12 is an arithmetic progression as 3 is added to each number