1. The problem is to convert the number 109 into Roman numerals. 2. Roman numerals use letters to represent values: I=1, V=5, X=10, L=50, C=100, D=500, M=1000. 3. To write 109, break it down into 100 + 9. 4. 100 is represented by C. 5. 9 is represented by IX (10 - 1). 6. Combine these parts: 109 = C + IX = CIX. 7. Therefore, the Roman numeral for 109 is **CIX**.