Dragonair can evolve into Dragonite by simply Leveling up to Lv.55.
Dragonair evolves at level 55
dragonair will evolve at lvl 54 or 56
dragonite
It evolves into Dragonair, and dragonair evolves into dragonite
Dragonair will evolve into Dragonite at Level 55.
Dratini evolves into Dragonair, starting at level 30. Dragonair, then, evolves into Dragonite at level 55.
lv 55
55
Level 55
Dragonair evolves into dragonite at level 56
It should evolve at Level 55.
Dragonair evolves at Level 55 in Pokémon FireRed.