What is the Greatest Common Factor of 309 and 315?

Greatest common factor (GCF) of 309 and 315 is 3.

GCF(309,315) = 3

We will now calculate the prime factors of 309 and 315, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 309 and 315.

How to find the GCF of 309 and 315?

We will first find the prime factorization of 309 and 315. After we will calculate the factors of 309 and 315 and find the biggest common factor number .

Step-1: Prime Factorization of 309

Prime factors of 309 are 3, 103. Prime factorization of 309 in exponential form is:

309 = 3¹ × 103¹

Step-2: Prime Factorization of 315

Prime factors of 315 are 3, 5, 7. Prime factorization of 315 in exponential form is:

315 = 3² × 5¹ × 7¹

Step-3: Factors of 309

List of positive integer factors of 309 that divides 309 without a remainder.

1, 3, 103

Step-4: Factors of 315

List of positive integer factors of 315 that divides 309 without a remainder.

1, 3, 5, 7, 9, 15, 21, 35, 45, 63, 105

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 309 and 315. The biggest common factor number is the GCF number.
So the greatest common factor 309 and 315 is 3.

Also check out the Least Common Multiple of 309 and 315