Is it true that any number that has nine as a factor also has three as a factor?

Question

Is it true that any number that has a nine as a factor also has three as a factor???

Answer 1

Yes, because multiplying factors equals the number.  So, if:

      9 * other = number             [that is, 9 is a factor of number]

  then:

      3 * (3*other) = number         [that is, 3 is a factor of number]

 

Answer 2

Yes, because 9 = 3², so 3 is a factor if 9 is a factor.