What is the greatest common factor of 28 and 77?

The greatest common factor of 28 and 77 is 7.

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

The factors of 28 are 1, 2, 4, 7, 14, and 28.

The factors of 77 are 1, 7, 11, and 77.

The common factors are 1 and 7. Therefore, the greatest common factor is 7.

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

The prime factors of 28 are 2, 2, and 7.

The prime factors of 77 are 7 and 11.

The prime factors in common are a single 7, so the greatest common factor is 7.

Summary of results:

The common factors are 1 and 7.

The greatest common factor is 7.