Answer:
MN = 3
Explanation:
The following are congruent to each other as each pair are tangents of a circle drawn from the same external point:
PQ = QJ = 1
JK = KL = 4 - 1 = 3
MN = ML
Thus, ML = KM - KL
ML = 6 - 3 = 3
Therefore, MN = ML = 3 (both are tangents drawn from the same external point, M.