Read this article to figure out how to calculate the lowest common denominator of . Learn the two different methods that you can use to find the LCD: the prime factorization method and the LCD formula method. We will explain both these methods in detail so stick around until the very end to understand. Utilise our free LCD Calculator to avail the LCD of numbers easily.
Given numbers are 21,79,90
We can find the LCD of numbers 21,79,90 by the prime factorization method or by applying the LCD formula.
The LCD of 21,79,90 is 49770.
3 | 21, 79, 90 |
7, 79, 30 |
As you can see, now we have to multiply the prime numbers on the left side with the co-primes at the bottom.
3 x 7 x 79 x 30 = 49770
Thus, we have determined that the LCD of 21,79,90 is 49770
The LCD formula is LCD(a,b) = ( a x b) / GCF(a,b)
Step1:
Find the GCF of 21 and 79. To find the GCF, list down the factors of 21 and 79 and select the highest factor that appears in both lists of factors.
21 : [1, 3, 7, 21]
79 : [1, 79]
From this, we can see that the GCF of 21 and 79 is 1.
Now, put this into the LCD formula.
LCD(21, 79) = ( 21 x 79 ) / 1
LCD(21, 79) = 1659 / 1
LCD(21, 79) = 1659
Step2:
Find the GCF of 1659 and 90. To find the GCF, list down the factors of 1659 and 90 and select the highest factor that appears in both lists of factors.
1659 : [1, 3, 7, 21, 79, 237, 553, 1659]
90 : [1, 2, 3, 5, 6, 9, 10, 15, 18, 30, 45, 90]
From this, we can see that the GCF of 1659 and 90 is 3.
Now, put this into the LCD formula.
LCD(1659, 90) = ( 1659 x 90 ) / 3
LCD(1659, 90) = 149310 / 3
LCD(1659, 90) = 49770
LCD of 21,79,90 is 49770
Here are some samples of LCD of Numbers calculations.
1. What is the LCD of ?
Answer: LCD of is .
2. How to find LCD of using prime factorization ?
Answer: Just keep dividing by prime numbers until only co-primes are left over. At that point, simply multiply the co-primes with the prime numbers on the left. The answer will be , the LCD.
3. How to Find the LCD of using LCD formula ?
Answer: The LCD formula is LCD(a,b) = ( a x b) / GCF(a,b).
You must first calculate the LCD OF and . Then, find the LCD of that answer and and so on. The answer will be , which is the LCD of .