Answer:
12
Step-by-step explanation:
The greatest common factor (GCF) is the largest factor two numbers share within their respective factor trees. In order to find the GCF, list factors of each number and then select the biggest one they have in common.
Factors of 108 are:
1, 108; 2, 54; 4, 27; 6, 18; 9, 12
Factors of 132 are:
1, 132; 2, 66; 3, 44; 4, 33; 6, 22; 11, 12
As can be observed, the largest number they have in common is 12. Therefore the GCF of 108 and 132 is 12.