LCM of 3 and 9
LCM of 3 and 9 is the smallest number among all common multiples of 3 and 9. The first few multiples of 3 and 9 are (3, 6, 9, 12, 15, . . . ) and (9, 18, 27, 36, 45, 54, 63, . . . ) respectively. There are 3 commonly used methods to find LCM of 3 and 9  by division method, by prime factorization, and by listing multiples.
1.  LCM of 3 and 9 
2.  List of Methods 
3.  Solved Examples 
4.  FAQs 
What is the LCM of 3 and 9?
Answer: LCM of 3 and 9 is 9.
Explanation:
The LCM of two nonzero integers, x(3) and y(9), is the smallest positive integer m(9) that is divisible by both x(3) and y(9) without any remainder.
Methods to Find LCM of 3 and 9
Let's look at the different methods for finding the LCM of 3 and 9.
 By Division Method
 By Prime Factorization Method
 By Listing Multiples
LCM of 3 and 9 by Division Method
To calculate the LCM of 3 and 9 by the division method, we will divide the numbers(3, 9) by their prime factors (preferably common). The product of these divisors gives the LCM of 3 and 9.
 Step 1: Find the smallest prime number that is a factor of at least one of the numbers, 3 and 9. Write this prime number(3) on the left of the given numbers(3 and 9), separated as per the ladder arrangement.
 Step 2: If any of the given numbers (3, 9) is a multiple of 3, divide it by 3 and write the quotient below it. Bring down any number that is not divisible by the prime number.
 Step 3: Continue the steps until only 1s are left in the last row.
The LCM of 3 and 9 is the product of all prime numbers on the left, i.e. LCM(3, 9) by division method = 3 × 3 = 9.
LCM of 3 and 9 by Prime Factorization
Prime factorization of 3 and 9 is (3) = 3^{1} and (3 × 3) = 3^{2} respectively. LCM of 3 and 9 can be obtained by multiplying prime factors raised to their respective highest power, i.e. 3^{2} = 9.
Hence, the LCM of 3 and 9 by prime factorization is 9.
LCM of 3 and 9 by Listing Multiples
To calculate the LCM of 3 and 9 by listing out the common multiples, we can follow the given below steps:
 Step 1: List a few multiples of 3 (3, 6, 9, 12, 15, . . . ) and 9 (9, 18, 27, 36, 45, 54, 63, . . . . )
 Step 2: The common multiples from the multiples of 3 and 9 are 9, 18, . . .
 Step 3: The smallest common multiple of 3 and 9 is 9.
∴ The least common multiple of 3 and 9 = 9.
☛ Also Check:
 LCM of 6 and 7  42
 LCM of 4 and 10  20
 LCM of 25 and 100  100
 LCM of 3 and 7  21
 LCM of 56 and 72  504
 LCM of 13 and 15  195
 LCM of 8 and 42  168
LCM of 3 and 9 Examples

Example 1: The GCD and LCM of two numbers are 3 and 9 respectively. If one number is 9, find the other number.
Solution:
Let the other number be m.
∵ GCD × LCM = 9 × m
⇒ m = (GCD × LCM)/9
⇒ m = (3 × 9)/9
⇒ m = 3
Therefore, the other number is 3. 
Example 2: Find the smallest number that is divisible by 3 and 9 exactly.
Solution:
The smallest number that is divisible by 3 and 9 exactly is their LCM.
⇒ Multiples of 3 and 9: Multiples of 3 = 3, 6, 9, 12, 15, 18, 21, . . . .
 Multiples of 9 = 9, 18, 27, 36, 45, 54, 63, . . . .
Therefore, the LCM of 3 and 9 is 9.

Example 3: The product of two numbers is 27. If their GCD is 3, what is their LCM?
Solution:
Given: GCD = 3
product of numbers = 27
∵ LCM × GCD = product of numbers
⇒ LCM = Product/GCD = 27/3
Therefore, the LCM is 9.
The probable combination for the given case is LCM(3, 9) = 9.
FAQs on LCM of 3 and 9
What is the LCM of 3 and 9?
The LCM of 3 and 9 is 9. To find the least common multiple (LCM) of 3 and 9, we need to find the multiples of 3 and 9 (multiples of 3 = 3, 6, 9, 12; multiples of 9 = 9, 18, 27, 36) and choose the smallest multiple that is exactly divisible by 3 and 9, i.e., 9.
What are the Methods to Find LCM of 3 and 9?
The commonly used methods to find the LCM of 3 and 9 are:
 Division Method
 Prime Factorization Method
 Listing Multiples
What is the Least Perfect Square Divisible by 3 and 9?
The least number divisible by 3 and 9 = LCM(3, 9)
LCM of 3 and 9 = 3 × 3 [No incomplete pair]
⇒ Least perfect square divisible by each 3 and 9 = 9 [Square root of 9 = √9 = ±3]
Therefore, 9 is the required number.
Which of the following is the LCM of 3 and 9? 15, 9, 2, 42
The value of LCM of 3, 9 is the smallest common multiple of 3 and 9. The number satisfying the given condition is 9.
If the LCM of 9 and 3 is 9, Find its GCF.
LCM(9, 3) × GCF(9, 3) = 9 × 3
Since the LCM of 9 and 3 = 9
⇒ 9 × GCF(9, 3) = 27
Therefore, the GCF (greatest common factor) = 27/9 = 3.