1. The problem asks us to identify which number among 4, 5, 9, and 15 is composite. 2. A composite number is a positive integer greater than 1 that has more than two distinct positive divisors (i.e., it can be divided evenly by numbers other than 1 and itself). 3. Let's check each number: - 4: Divisors are 1, 2, and 4. Since it has more than two divisors, 4 is composite. - 5: Divisors are 1 and 5 only. So, 5 is prime, not composite. - 9: Divisors are 1, 3, and 9. More than two divisors, so 9 is composite. - 15: Divisors are 1, 3, 5, and 15. More than two divisors, so 15 is composite. 4. Therefore, the composite numbers in the list are 4, 9, and 15. 5. Since the question asks which number is composite (singular), the first composite number in the list is 4. Final answer: 4 is composite.