The greatest common factor of 15 and 45 is:

03

5

015

45

15

Step-by-step explanation:

We can find the greatest common factor by listing the factors of the 2 numbers, that is

Factors of 15 are 1, 3, 5, 15

Factors of 45 are 1, 3, 5, 9, 15, 45

The common factors are 1, 3, 5, 15

The greatest common factor is 15