The answer is 9
Explained:
GCF of 72 and 81 by Listing Common Factors
Factors of 72: 1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 36, 72
Factors of 81: 1, 3, 9, 27, 81
There are 3 common factors of 72 and 81, that are 1, 3, and 9. Therefore, the greatest common factor of 72 and 81 is 9.
