Created By : Jatin Gogia
Reviewed By : Rajasekhar Valipishetty
Last Updated : Apr 06, 2023
Free LCM Calculator determines the least common multiple (LCM) between 84 and 90 the smallest integer that is 1260 that is divisible by both numbers.
Least Common Multiple (LCM) of 84 and 90 is 1260.
LCM(84,90) = 1260
Least common multiple or lowest common denominator (LCD) can be calculated in three ways;
Least common multiple can be found by multiplying the highest exponent prime factors of 84 and 90. First we will calculate the prime factors of 84 and 90.
Prime Factorization of 84
2 | 84 |
2 | 42 |
3 | 21 |
7 | 7 |
1 |
Prime factors of 84 are 2, 3,7. Prime factorization of 84 in exponential form is:
84 = 22×31×71
Prime Factorization of 90
2 | 90 |
3 | 45 |
3 | 15 |
5 | 5 |
1 |
Prime factors of 90 are 2, 3,5. Prime factorization of 90 in exponential form is:
90 = 21×32×51
Now multiplying the highest exponent prime factors to calculate the LCM of 84 and 90.
LCM(84,90) = 22×32×51×71
LCM(84,90) = 1260
Factors of 84
List of positive integer factors of 84 that divides 84 without a remainder.
1, 2, 3, 4, 6, 7, 12, 14, 21, 28, 42, 84
Factors of 90
List of positive integer factors of 90 that divides 90 without a remainder.
1, 2, 3, 5, 6, 9, 10, 15, 18, 30, 45, 90
The formula of LCM is LCM(a,b) = ( a × b) / GCF(a,b).
We need to calculate greatest common factor 84 and 90, than apply into the LCM equation.
GCF(84,90) = 6
LCM(84,90) = ( 84 × 90) / 6
LCM(84,90) = 7560 / 6
LCM(84,90) = 1260
(i) The LCM of 90 and 84 is associative
LCM of 84 and 90 = LCM of 90 and 84
1. What is the LCM of 84 and 90?
Answer: LCM of 84 and 90 is 1260.
2. What are the Factors of 84?
Answer: Factors of 84 are 1, 2, 3, 4, 6, 7, 12, 14, 21, 28, 42, 84. There are 12 integers that are factors of 84. The greatest factor of 84 is 84.
3. What are the Factors of 90?
Answer: Factors of 90 are 1, 2, 3, 5, 6, 9, 10, 15, 18, 30, 45, 90. There are 12 integers that are factors of 90. The greatest factor of 90 is 90.
4. How to Find the LCM of 84 and 90?
Answer:
Least Common Multiple of 84 and 90 = 1260
Step 1: Find the prime factorization of 84
84 = 2 x 2 x 3 x 7
Step 2: Find the prime factorization of 90
90 = 2 x 3 x 3 x 5
Step 3: Multiply each factor the greater number of times it occurs in steps i) or ii) above to find the lcm:
LCM = 1260 = 2 x 2 x 3 x 3 x 5 x 7
Step 4: Therefore, the least common multiple of 84 and 90 is 1260.