u cant, fire red and leaf green are re-make of the first three games (red, blue and yellow version). so any Pokemon past the first 151 in the total list is not possible (there are some glich Pokemon that are not on the list but are possible, example missnigno.
It is Pupitar.
it evolves at level 55.
Train a larvitar to level 35.
You have to trade from LeafGreen/FireRed.
at level 30 it evolves to pupitar, and at level 55 pupitar evolves into tyranitar
Evolve Larvitar, which you get at Seavault Canyon on Seven Island.
It's actually impossible to catch Pupitar in Pokemon Emerald. The only way to get it is to trade it from LeafGreen and FireRed. Hope I helped :)
Pupitar at level 30 and into tyranitar at level 55.
Tyranitar isn't anywhere in the wild in Pokemon FireRed. You will need to evolve it from Pupitar. It is required to get a Larvitar first, however; it is in Seavault Cave and can evolve into Pupitar at level 30, then Pupitar into Tyranitar at level 55.
Larvitar evolves into Pupitar at Level 30 and then Tyranitar at Level 55.
LEVEL: 72
You must train a Larvitar to level 30 or so in order for it to evolve to Pupitar.