What is the least common factor of 15 and 18?

The correct answer is:  " 3" . 

The "least common factor (LCF)" of "15" and "18" is:  " 3 " .

Note:  List the factors for BOTH "15" and for "18" :

 
  15:  1, 3, 5, 15 .

  18:  1, 2, 3, 6, 9, 18 .

NOTE:
      Among the factors for BOTH "15" and "18" ; the lowest value (i.e. "lowest factor other than "1") that both numbers share is:  " 3 " .

Hello! mark me brainliest
answer:
congruent segments
step-by-step explanation:
congruent segments. take a line, cut it in half, superipose one half over the other half; you'll have congruence.