Respuesta :
You need to find the common primes...
18=2*3*3 and 72=2*2*2*3*3 so they have 2*3*3 in common and
2*3*3=18
So 18 is the greatest common factor.
18=2*3*3 and 72=2*2*2*3*3 so they have 2*3*3 in common and
2*3*3=18
So 18 is the greatest common factor.
Greatest Common Factor(GCF): Largest factor of two or more numbers
Factors of 18: 1, 2, 3, 6, 9, 18
Factors of 72: 1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 36, 72
Largest number in both of the lists: 18
GCF: 18
Factors of 18: 1, 2, 3, 6, 9, 18
Factors of 72: 1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 36, 72
Largest number in both of the lists: 18
GCF: 18