MN = y
1.
NP = MN - 2 = y - 2
PK = 2 * MN = 2y
MK = PK + 2 = 2y + 2
2.
P = MN + NP + PK + MK = y + y - 2 + 2y + 2y + 2 = 6y = 24
3.
6y = 4
y = 4
MN = y = 4 см
