GCF of 28 and 45
GCF of 28 and 45 is the largest possible number that divides 28 and 45 exactly without any remainder. The factors of 28 and 45 are 1, 2, 4, 7, 14, 28 and 1, 3, 5, 9, 15, 45 respectively. There are 3 commonly used methods to find the GCF of 28 and 45  prime factorization, long division, and Euclidean algorithm.
1.  GCF of 28 and 45 
2.  List of Methods 
3.  Solved Examples 
4.  FAQs 
What is GCF of 28 and 45?
Answer: GCF of 28 and 45 is 1.
Explanation:
The GCF of two nonzero integers, x(28) and y(45), is the greatest positive integer m(1) that divides both x(28) and y(45) without any remainder.
Methods to Find GCF of 28 and 45
Let's look at the different methods for finding the GCF of 28 and 45.
 Long Division Method
 Prime Factorization Method
 Using Euclid's Algorithm
GCF of 28 and 45 by Long Division
GCF of 28 and 45 is the divisor that we get when the remainder becomes 0 after doing long division repeatedly.
 Step 1: Divide 45 (larger number) by 28 (smaller number).
 Step 2: Since the remainder ≠ 0, we will divide the divisor of step 1 (28) by the remainder (17).
 Step 3: Repeat this process until the remainder = 0.
The corresponding divisor (1) is the GCF of 28 and 45.
GCF of 28 and 45 by Prime Factorization
Prime factorization of 28 and 45 is (2 × 2 × 7) and (3 × 3 × 5) respectively. As visible, there are no common prime factors between 28 and 45, i.e. they are coprime. Hence, the GCF of 28 and 45 will be 1.
GCF of 28 and 45 by Euclidean Algorithm
As per the Euclidean Algorithm, GCF(X, Y) = GCF(Y, X mod Y)
where X > Y and mod is the modulo operator.
Here X = 45 and Y = 28
 GCF(45, 28) = GCF(28, 45 mod 28) = GCF(28, 17)
 GCF(28, 17) = GCF(17, 28 mod 17) = GCF(17, 11)
 GCF(17, 11) = GCF(11, 17 mod 11) = GCF(11, 6)
 GCF(11, 6) = GCF(6, 11 mod 6) = GCF(6, 5)
 GCF(6, 5) = GCF(5, 6 mod 5) = GCF(5, 1)
 GCF(5, 1) = 1 (∵ GCF(X, 1) = 1)
Therefore, the value of GCF of 28 and 45 is 1.
☛ Also Check:
 GCF of 68 and 102 = 34
 GCF of 64 and 144 = 16
 GCF of 51 and 85 = 17
 GCF of 15 and 18 = 3
 GCF of 75, 8 and 21 = 1
 GCF of 63 and 81 = 9
 GCF of 30 and 105 = 15
GCF of 28 and 45 Examples

Example 1: For two numbers, GCF = 1 and LCM = 1260. If one number is 28, find the other number.
Solution:
Given: GCF (z, 28) = 1 and LCM (z, 28) = 1260
∵ GCF × LCM = 28 × (z)
⇒ z = (GCF × LCM)/28
⇒ z = (1 × 1260)/28
⇒ z = 45
Therefore, the other number is 45. 
Example 2: The product of two numbers is 1260. If their GCF is 1, what is their LCM?
Solution:
Given: GCF = 1 and product of numbers = 1260
∵ LCM × GCF = product of numbers
⇒ LCM = Product/GCF = 1260/1
Therefore, the LCM is 1260. 
Example 3: Find the greatest number that divides 28 and 45 exactly.
Solution:
The greatest number that divides 28 and 45 exactly is their greatest common factor, i.e. GCF of 28 and 45.
⇒ Factors of 28 and 45: Factors of 28 = 1, 2, 4, 7, 14, 28
 Factors of 45 = 1, 3, 5, 9, 15, 45
Therefore, the GCF of 28 and 45 is 1.
FAQs on GCF of 28 and 45
What is the GCF of 28 and 45?
The GCF of 28 and 45 is 1. To calculate the greatest common factor of 28 and 45, we need to factor each number (factors of 28 = 1, 2, 4, 7, 14, 28; factors of 45 = 1, 3, 5, 9, 15, 45) and choose the greatest factor that exactly divides both 28 and 45, i.e., 1.
What are the Methods to Find GCF of 28 and 45?
There are three commonly used methods to find the GCF of 28 and 45.
 By Prime Factorization
 By Euclidean Algorithm
 By Long Division
How to Find the GCF of 28 and 45 by Long Division Method?
To find the GCF of 28, 45 using long division method, 45 is divided by 28. The corresponding divisor (1) when remainder equals 0 is taken as GCF.
What is the Relation Between LCM and GCF of 28, 45?
The following equation can be used to express the relation between LCM and GCF of 28 and 45, i.e. GCF × LCM = 28 × 45.
How to Find the GCF of 28 and 45 by Prime Factorization?
To find the GCF of 28 and 45, we will find the prime factorization of the given numbers, i.e. 28 = 2 × 2 × 7; 45 = 3 × 3 × 5.
⇒ There is no common prime factor for 28 and 45. Hence, GCF (28, 45) = 1.
☛ What are Prime Numbers?
If the GCF of 45 and 28 is 1, Find its LCM.
GCF(45, 28) × LCM(45, 28) = 45 × 28
Since the GCF of 45 and 28 = 1
⇒ 1 × LCM(45, 28) = 1260
Therefore, LCM = 1260
☛ GCF Calculator
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