The greatest common factor (GCF) of the numbers 3, 15, and 9 is 3.
To find the GCF, we first list the factors of each number:
- Factors of 3: 1, 3
- Factors of 15: 1, 3, 5, 15
- Factors of 9: 1, 3, 9
Next, we identify the common factors from these lists. The numbers that appear in all three lists are:
- 1
- 3
Among these common factors, the greatest is 3. Therefore, the greatest common factor of 3, 15, and 9 is 3.