GCD of 28, 15, 78, 21 Calculator
Reviewed By : Phani Ponnapalli
Last Updated at : Mar 29,2023
Online GCD Calculator is useful to find the GCD of 28, 15, 78, 21 quickly. Get the easiest ways to solve the greatest common divisor of 28, 15, 78, 21 i.e 1 in different methods as follows.
Given Input numbers are 28, 15, 78, 21
In the factoring method, we have to find the divisors of all numbers
Divisors of 28 :
The positive integer divisors of 28 that completely divides 28 are.
1, 2, 4, 7, 14, 28
Divisors of 15 :
The positive integer divisors of 15 that completely divides 15 are.
1, 3, 5, 15
Divisors of 78 :
The positive integer divisors of 78 that completely divides 78 are.
1, 2, 3, 6, 13, 26, 39, 78
Divisors of 21 :
The positive integer divisors of 21 that completely divides 21 are.
1, 3, 7, 21
GCD of numbers is the greatest common divisor
So, the GCD (28, 15, 78, 21) = 1.
Given numbers are 28, 15, 78, 21
The list of prime factors of all numbers are
Prime factors of 28 are 2 x 2 x 7
Prime factors of 15 are 3 x 5
Prime factors of 78 are 2 x 3 x 13
Prime factors of 21 are 3 x 7
The above numbers do not have any common prime factor. So GCD is 1
Steps to Calculate GCD of 28, 15, 78, 21 using LCM Formula
Given numbers are 28, 15, 78, 21
GCD of 2 numbers formula is GCD(a, b) = ( a x b) / LCM(a, b)
Apply this formula for all numbers.
Step1:
LCM(28, 15) = 420
GCD(28, 15) = ( 28 x 15 ) / 420
= 28 / 15
= 28
Step2:
LCM(1, 78) = 78
GCD(1, 78) = ( 1 x 78 ) / 78
= 1 / 78
= 1
Step3:
LCM(1, 21) = 21
GCD(1, 21) = ( 1 x 21 ) / 21
= 1 / 21
= 1
So, Greatest Common Divisor of 28, 15, 78, 21 is 1
GCD of Numbers Calculation Examples
Here are some samples of GCD of Numbers calculations.
Greatest Common Divisor of 28, 15, 78, 21
Given numbers are 28, 15, 78, 21
The greatest common divisor of numbers 28, 15, 78, 21 can be found in various methods such as the LCM formula, factoring, and prime factorization. The GCD of numbers 28, 15, 78, 21 is 1.
FAQs on GCD of 28, 15, 78, 21 Calculator
1. What is the GCD of 28, 15, 78, 21?
GCD of given numbers 28, 15, 78, 21 is 1
2. How to calculate the greatest common divisor of 28, 15, 78, 21?
We can find the highest common divisor of 28, 15, 78, 21 easily using the prime factorization method. Just list the prime factors of all numbers and pick the highest common factor which is the GCD of 28, 15, 78, 21 i.e 1.
3. How can I use the GCD of 28, 15, 78, 21Calculator?
Out the numbers 28, 15, 78, 21 into the GCD calculator and hit the calculate button to get the greatest common divisor as result.