Given numbers:
In getting the GCF of the numbers, let's list down the possible factors of each number.
Factors of 30: 1, 2, 3, 5, 6, 10, 15, 30
Factors of 45: 1, 3, 5, 9, 15, 45
It's been determined that 30 and 45 has the highest common factor of 15.
Therefore, GCF of 30 and 45 = 15.
The answer is No, 3 is not the GCF of 30 and 45.