Find Least Common Multiple of 15, 30 and 45 using prime factorisation method.
Answer
LCM( 15, 30, 45 ) = 90
Explanation
Step 1: Write down factorisation of each number:
15 = 3 · 5
30 = 2 · 3 · 5
45 = 3 · 3 · 5
Step 2 : Match primes vertically:
| 15 | = | 3 | · | 5 | ||||
| 30 | = | 2 | · | 3 | · | 5 | ||
| 45 | = | 3 | · | 3 | · | 5 |
Step 3 : Bring down numbers in each column and multiply to get LCM:
| 15 | = | 3 | · | 5 | ||||||
| 30 | = | 2 | · | 3 | · | 5 | ||||
| 45 | = | 3 | · | 3 | · | 5 | ||||
| LCM | = | 2 | · | 3 | · | 3 | · | 5 | = | 90 |
This solution can be visualized using a Venn diagram.
The LCM is equal to the product of all the numbers on the diagram.
This page was created using
LCM Calculator