What is the greatest common factor of 39 and 65?

The GCF of 39 and 65 is 13.

One way to determine the greatest common factor is to find all the factors of the numbers and compare them.

The factors of 39 are 1, 3, 13, and 39.

The factors of 65 are 1, 5, 13, and 65.

The common factors are 1 and 13. Therefore, the greatest common factor is 13.

The greatest common factor can also be calculated by identifying the common prime factors and multiplying them together.

The prime factors of 39 are 3 and 13.

The prime factors of 65 are 5 and 13.

The prime factors in common are a single 13, so the greatest common factor is 13.