Question: how to find greatest common factor for 36 and 45?
Answer: The prime factorization of 36 is: 2 x 2 x 3 x 3.
The prime factorization of 45 is: 3 x 3 x 5.
The prime factors and multiplicities 36 and 45 have in common are: 3 x 3.
3 x 3 is the gcf of 36 and 45.
gcf(36,45) = 9.