Answer :

Answer:

  (b)  8 cm

Step-by-step explanation:

You want to know the length of segment LN with midpoint M and the length of LM given as 4 cm.

Segment addition

The segment addition theorem tells you the length of a line segment is equal to the sum of the lengths of its parts.

  LN = LM +MN

Markings

The hash marks on segments LM and MN mean those segments have the same length. Then the sum is ...

  LN = (4 cm) +(4 cm) = 8 cm

The length of segment LN is 8 cm.