Solution: The LCM of 72 and 121 is 8712
Methods
How to find the LCM of 72 and 121 using Prime Factorization
One way to find the LCM of 72 and 121 is to start by comparing 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 72?
What are the Factors of 121?
Here is the prime factorization of 72:
2
3
×
3
2
2^3 × 3^2
2 3 × 3 2
And this is the prime factorization of 121:
1
1
2
11^2
1 1 2
When you compare the prime factorization of these two numbers, you want to look for the highest power that each prime factor is raised to. In this case, there are these prime factors to consider: 2, 3, 11
2
3
×
3
2
×
1
1
2
=
8712
2^3 × 3^2 × 11^2 = 8712
2 3 × 3 2 × 1 1 2 = 8712
Through this we see that the LCM of 72 and 121 is 8712.
How to Find the LCM of 72 and 121 by Listing Common Multiples
The first step to this method of finding the Least Common Multiple of 72 and 121 is to begin to list a few multiples for each number. If you need a refresher on how to find the multiples of these numbers, you can see the walkthroughs in the links below for each number.
Let’s take a look at the multiples for each of these numbers, 72 and 121:
What are the Multiples of 72?
What are the Multiples of 121?
Let’s take a look at the first 10 multiples for each of these numbers, 72 and 121:
First 10 Multiples of 72: 72, 144, 216, 288, 360, 432, 504, 576, 648, 720
First 10 Multiples of 121: 121, 242, 363, 484, 605, 726, 847, 968, 1089, 1210
You can continue to list out the multiples of these numbers as long as needed to find a match. Once you do find a match, or several matches, the smallest of these matches would be the Least Common Multiple. For instance, the first matching multiple(s) of 72 and 121 are 8712, 17424, 26136. Because 8712 is the smallest, it is the least common multiple.
The LCM of 72 and 121 is 8712.
Find the LCM of Other Number Pairs
Want more practice? Try some of these other LCM problems:
What is the LCM of 138 and 43?
What is the LCM of 141 and 79?
What is the LCM of 130 and 23?
What is the LCM of 61 and 148?
What is the LCM of 41 and 56?