Point M is the midpoint of side AC of triangle ABC, side AB is 2 mm less than side BC, perimeter

Point M is the midpoint of side AC of triangle ABC, side AB is 2 mm less than side BC, perimeter of triangle ABM is 16 mm. Find the perimeter of triangle BCM.

The ABM triangle has a common side with the MBC triangle. Since the AC side is divided by the point M into two equal segments, the sides AM and MC of triangles ABM and MBC are also equal. The only difference between the triangles is sides AB and BC, but we know from the problem statement that BC is 2 mm less than the BC side. That is, the perimeters of the two triangles also differ by 2 mm.
Find the perimeter of the MBS triangle:
16 + 2 = 18 (mm).
ANSWER: The perimeter of the MBC triangle is 18 mm.