Answer:
72
Explanation:
Well, 3/12 can be simplified to 1/4
To find the least common denominator of 1/8, 2/9, and 1/4 make a list of multiples that they have in common
8: 8, 16, 24, 32, 40, 48, 56, 64, 72...
9: 9, 18, 27, 36, 45, 54, 63, 72...
4: 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48, 52, 56, 60, 64, 68, 72...
As you can see, 72 is the one number they all have in common which makes it the least common denominator.