What is the next number in the following pattern: 3, 6, 9, ...?

The sequence provided—3, 6, 9—follows a clear pattern where each number increases by 3. This is an example of an arithmetic sequence, where the common difference between consecutive terms is consistent.

Starting with the first number, 3:

• To get to the second number, 6, you add 3 (3 + 3 = 6).

• To reach the third number, 9, you again add 3 (6 + 3 = 9).

Continuing this pattern, if you add 3 to 9, you obtain the next number:

9 + 3 = 12.

This confirms that the next number in the sequence is 12, aligning with the choice given. This systematic approach to recognizing patterns in sequences is essential in mathematics, particularly when working with arithmetic progressions.