Any multiple of 45.
Multiples of 15 include 15, 30 and 45. For them to be common, they need to be compared to another set of multiples.
There are infinite common multiples for a set of numbers. So it is not possible to write down all the common multiples. Some common multiples of 15, 30 and 45 are 90, 180, 270, 360,... There is another way to find common multiples: Write the multiples of LCM(15, 30, 45). Actually the common multiples of a set of numbers are the multiples of their LCM. LCM of 15, 30 and 45 is 90. And the multiples of 90 are 90, 180, 270, 360, 450, 540,... which are the common multiples of 15, 30 and 45.
The Least Common Multiple of 9 and 15 is 45.
Multiples of 15 include 15, 30 and 45. For them to be common, they need to be compared to another set of multiples.
The multiples of 15 are 15, 30, 45, 60, 75 and so on. For them to be common, they need to be compared to another set of multiples.
45 1*45 = 45 3*15 = 45
15, 30, and 45
15, 30, 45 and so on.
Since 3 is a factor of 15, the first three common multiples of 3 and 15 are 15, 30, and 45.
15, 30, 45
15, 30, 45 and so on.
The common multiples of 3 and 15 from 1 to 100 are 15, 30, 45, 60, 75, 90