The greatest common factor (GCF) of 18, 36, and 45 is 9.
To find the GCF, we first list the factors of each number:
- Factors of 18: 1, 2, 3, 6, 9, 18
- Factors of 36: 1, 2, 3, 4, 6, 9, 12, 18, 36
- Factors of 45: 1, 3, 5, 9, 15, 45
Next, we identify the common factors of all three numbers. The common factors are 1, 3, and 9. The greatest of these is 9, so the GCF of 18, 36, and 45 is 9.