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 20,90,78
We can find the LCD of numbers 20,90,78 by the prime factorization method or by applying the LCD formula.
The LCD of 20,90,78 is 2340.
2 | 20, 90, 78 |
3 | 10, 45, 39 |
5 | 10, 15, 13 |
2, 3, 13 |
As you can see, now we have to multiply the prime numbers on the left side with the co-primes at the bottom.
2 x 3 x 5 x 2 x 3 x 13 = 2340
Thus, we have determined that the LCD of 20,90,78 is 2340
The LCD formula is LCD(a,b) = ( a x b) / GCF(a,b)
Step1:
Find the GCF of 20 and 90. To find the GCF, list down the factors of 20 and 90 and select the highest factor that appears in both lists of factors.
20 : [1, 2, 4, 5, 10, 20]
90 : [1, 2, 3, 5, 6, 9, 10, 15, 18, 30, 45, 90]
From this, we can see that the GCF of 20 and 90 is 10.
Now, put this into the LCD formula.
LCD(20, 90) = ( 20 x 90 ) / 10
LCD(20, 90) = 1800 / 10
LCD(20, 90) = 180
Step2:
Find the GCF of 180 and 78. To find the GCF, list down the factors of 180 and 78 and select the highest factor that appears in both lists of factors.
180 : [1, 2, 3, 4, 5, 6, 9, 10, 12, 15, 18, 20, 30, 36, 45, 60, 90, 180]
78 : [1, 2, 3, 6, 13, 26, 39, 78]
From this, we can see that the GCF of 180 and 78 is 6.
Now, put this into the LCD formula.
LCD(180, 78) = ( 180 x 78 ) / 6
LCD(180, 78) = 14040 / 6
LCD(180, 78) = 2340
LCD of 20,90,78 is 2340
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 .