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What is the greatest common factor of 15 and 20 using prime factors?
Wiki User
∙ 11y ago
Prime factors of 15 are 3 x 5
Prime factors of 20 are 2 x 2 x 5
5 is the greatest common factor of 15 and 20.
Wiki User
∙ 11y ago
Wiki User
∙ 11y ago3 x 5 = 15
2 x 2 x 5 = 20
The GCF is 5.
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Why do you need the common prime factors when finding the greatest common factor?
You do not necessarily need the common prime factors when finding the greatest common factor, but with large numbers or numbers for which you cannot easily determine all the factors, using prime factorization to determine the greatest common factor is the easiest method. The greatest common factor can then be determined by multiplying the common prime factors together. For example, when trying to find the greatest common factor of 2144 and 5672, finding all their possible factors to compare could be difficult. So, it is easier to find their prime factors, determine the prime factors they have in common, and then multiply the common prime factors to get the greatest common factor. For descriptions and examples of finding the greatest common factor, see the "Related Questions" links below.
What is the greatest common factor of 35 and 42?
The greatest common factor can also be calculated by identifying the common prime factors and multiplying them together. The prime factors of 35 are 5 and 7. The prime factors of 42 are 2, 3, and 7. The common prime factors are a single 7, so the greatest common factor is 7.
What is the greatest common factor of 22 and 55?
The factors of 22 are 1, 2, 11, and 22. The factors of 55 are 1, 5, 11, and 55. The common factors are 1 and 11. Therefore, the greatest common factor is 11. The greatest common factor can also be find by determining the prime factors and multiplying the common prime factors together. The prime factors of 22 are 2 and 11. The prime factors of 55 are 5 and 11. The common prime factors are a single 11, so the greatest common factor is 11.
What is the greatest common factor of 5 and 23?
Because both numbers are prime numbers, the only common factor they have is 1. Therefore, the greatest common factor is 1. Another way to determine the greatest common factor is to find all the factors of the numbers and compare them. The factors of 5 are 1 and 5. The factors of 23 are 1 and 23. The only common factor is 1. Therefore, the greatest common factor is 1, which means the numbers are relatively prime. The greatest common factor can also be calculated by identifying the common prime factors and multiplying them together. The prime factor of 5 is 5. The prime factor of 23 is 23. There are no prime factors in common, so the numbers are relatively prime, which means the greatest common factor is 1.
What is the greatest common factor of 3 and 51?
3 is a factor of 51, and 3 is also the largest factor of itself, so 3 is the greatest common factor. The factors of 3 are 1 and 3. The factors of 51 are 1, 3, 17, and 51. The common factors are 1 and 3. Therefore, the greatest common factor is 3. The greatest common factor can also be calculated by identifying the common prime factors and multiplying them together. The prime factor of 3 is 3. The prime factors of 51 are 3 and 17. The common prime factors are a single 3, so the greatest common factor is 3.
How do you find the greatest common factor of 45 using prime factorization?
You do not. To have a greatest common factor, you need two or more numbers. A common factor is a factor that two or more number have in common. However, the prime factorization of all the numbers will help you find the greatest common factor. The greatest common factor will be the prime factors they have in common multiplied together. Example: The prime factors of 45 are 3, 3, and 5. The prime factors of 60 are 2, 2, 3, and 5. The common prime factors are 3 and 5, so the greatest common factor is 3 x 5 = 15.
What is the greatest common factor of 3 and 14?
Since 3 is a prime number, either it or 1 is the greatest common factor. Since 3 is not a factor of 14, the greatest common factor is 1. Another way to determine the greatest common factor is to find all the factors of the numbers and compare them. The factors of 3 are 1 and 3. The factors of 14 are 1, 2, 7, and 14. The only common factor is 1. Therefore, the greatest common factor is 1. The greatest common factor can also be calculated by identifying the common prime factors and multiplying them together. The prime factor of 3 is 3. The prime factors of 14 are 2 and 7. There are no prime factors in common, so the numbers are relatively prime, which means the greatest common factor is 1. Summary of results: The common factor is 1. The greatest common factor is 1. The numbers are relatively prime.
What is the greatest common factor of 15 and 39?
The factors of 15 are 1, 3, 5, and 15. The factors of 39 are 1, 3, 13, and 39. The factors they have in common are 1 and 3. Therefore, the greatest common factor is 3. You can also determine the greatest common factor from their prime factors. The prime factors of 15 are 3 and 5. The prime factors of 39 are 3 and 13. The prime factors they have in common are a single 3, so the greatest common factor is 3.
What is the greatest common factor of 51 and 119?
The factors of 51 are 1, 3, 17, and 51. The factors of 119 are 1, 7, 17, and 119. The factors they have in common are 1 and 17. Therefore the greatest common factor is 17. The greatest common factor can also be determined from the prime factors. The prime factors of 51 are 3 and 17. The prime factors of 119 are 7 and 17. The prime factors they have in common are a single 17, so the greatest common factor is 17.
What is the greatest common factor of 289 and 589?
1 One way to determine the greatest common factor is to find all the factors of the numbers and compare them. The factors of 289 are 1, 17, and 289. The factors of 589 are 1, 19, 31, and 589. The common factors are 1. Therefore, the greatest common factor is 1; they are relatively prime. The greatest common factor can also be calculated by identifying the common prime factors and multiplying them together. The prime factors of 289 are 17 and 17. The prime factors of 589 are 19 and 31. There are no prime factors in common, which means they are relatively prime, so the greatest common factor is 1.
What is the greatest prime factor of 40 and 63?
The greatest prime factor of 40 is 5. The greatest prime factor of 63 is 7. They do not have any prime factors in common.
What is the greatest common factor of 3 and 22?
Since 3 is a prime number, its only factors are 1 and 3, so the greatest common factor of 3 and 22 must be either 1 or 3. Since 3 does not divide 22, the greatest common factor is 1. Another way to determine the greatest common factor is to find all the factors of the numbers and compare them. The factors of 3 are 1 and 3. The factors of 22 are 1, 2, 11, and 22. The only common factor is 1. Therefore, the greatest common factor is 1. The greatest common factor can also be calculated by identifying the common prime factors and multiplying them together. The prime factor of 3 is 3. The prime factors of 22 are 2 and 11. There are no prime factors in common, so the numbers are relatively prime, which means their greatest common factor is 1.
