MATH SOLVE

3 months ago

Q:
# What is the GCF of 77 and 91?

Accepted Solution

A:

Solution: The GCF of 77 and 91 is 7
Methods
How to find the GCF of 77 and 91 using Prime Factorization
One way to find the GCF of 77 and 91 is to compare the prime factorization of each number. To find the prime factorization, you can follow the instructions for each number here:
What are the Factors of 77?
What are the Factors of 91?
Here is the prime factorization of 77:
7
1
×
1
1
1
7^1 × 11^1
7 1 × 1 1 1
And this is the prime factorization of 91:
7
1
×
1
3
1
7^1 × 13^1
7 1 × 1 3 1
When you compare the prime factorization of these two numbers, you can see that there are matching prime factors. You can now find the Greatest Common Factor of 77 and 91 by multiplying all the matching prime factors to get a GCF of 77 and 91 as 49:
Thus, the GCF of 77 and 91 is: 49
How to Find the GCF of 77 and 91 by Listing All Common Factors
The first step to this method of finding the Greatest Common Factor of 77 and 91 is to find and list all the factors of each number. Again, you can see how this is done by looking at the “Factors of” articles that are linked to above.
Let’s take a look at the factors for each of these numbers, 77 and 91:
Factors of 77: 1, 7, 11, 77
Factors of 91: 1, 7, 13, 91
When you compare the two lists of factors, you can see that the common factor(s) are 1, 7. Since 7 is the largest of these common factors, the GCF of 77 and 91 would be 7.
Find the GCF of Other Number Pairs
Want more practice? Try some of these other GCF problems:
What is the GCF of 47 and 10?
What is the GCF of 66 and 1?
What is the GCF of 72 and 21?
What is the GCF of 146 and 147?
What is the GCF of 100 and 4?