Created By : Jatin Gogia
Reviewed By : Rajasekhar Valipishetty
Last Updated : Apr 06, 2023
Make use of GCF Calculator to quickly find the Greatest Common Factor of numbers 78, 85 i.e. 1 largest integer by which both the numbers can be divided.
Greatest common factor (GCF) of 78 and 85 is 1.
GCF(78,85) = 1
Greatest common factor or Greatest common divisor (GCD) can be calculated in following way;
Prime Factorization of 78
2 | 78 |
3 | 39 |
13 | 13 |
1 |
Prime factors of 78 are 2,3,13. Prime factorization of 78 in exponential form is:
78 = 21×31×131
Prime Factorization of 85
5 | 85 |
17 | 17 |
1 |
Prime factors of 85 are 5,17. Prime factorization of 85 in exponential form is:
85 = 51×171
∴ So by taking common prime factors GCF of 78 and 85 is 1
Factors of 78
List of positive integer factors of 78 that divides 78 without a remainder.
1,2,3,6,13,26,39,78
Factors of 85
List of positive integer factors of 85 that divides 85 without a remainder.
1,5,17,85
Greatest Common Factor
We found the factors and prime factorization of 78 and 85. The biggest common factor number is the GCF number.
So the greatest common factor 78 and 85 is 1.
Also check out the Least Common Multiple of 78 and 85
(i) The GCF of 78 and 85 is associative
GCF of 78 and 85 = GCF of 85 and 78
1. What is the GCF of 78 and 85?
Answer: GCF of 78 and 85 is 1.
2. What are the Factors of 78?
Answer: Factors of 78 are 1, 2, 3, 6, 13, 26, 39, 78. There are 8 integers that are factors of 78. The greatest factor of 78 is 78.
3. What are the Factors of 85?
Answer: Factors of 85 are 1, 5, 17, 85. There are 4 integers that are factors of 85. The greatest factor of 85 is 85.
4. How to Find the GCF of 78 and 85?
Answer:
Greatest Common Factor of 78 and 85 = 1
Step 1: Find the prime factorization of 78
78 = 2 x 3 x 13
Step 2: Find the prime factorization of 85
85 = 5 x 17
Step 3: Multiply those factors both numbers have in common in steps i) or ii) above to find the gcf:
GCF = = 1
Step 4: Therefore, the greatest common factor of 78 and 85 is 1