Answer: GCF of 54 and 45: 9.
Step-by-step explanation: The factors of 54 include: 1, 2, 3, 6, 9, 18, 27, and 54. The factors of 45 include: 1, 3, 5, 9, 15, and 45. The largest common factor of 45 and 54 is 9.