It is 3
Yes. 15 and 18 have a common factor of 3. Divide the numerator and denominator by their common factor.
It will be 15
15
3
It is: 15
3
the least common multiple of 15,9,and 12 is 180.
3
15
It is 120.
945 is the lowest common denominator. 3 is the greatest common factor.
20, although if you reduced 15/20 to 3/4, the common denominator would be 4.