Get the national pokedex and go to the Great Marsh. trust me i got this info from Bulbapedia.
you find kangaskhan in area 2 of the safari zone in Pokemon leaf Green ... not sure in fire red sorry
you need to find it in the safari zone in area1.
Since it's a Kanto Pokemon, it must be traded from FR/LG.
Kangaskhan can only be found in certain areas of the Safrai Zone, located in Fuchsia City. The first area Kangaskhan can be found in is in the grass east of the entrance area. There is a 4% chance of Kangaskhan appearing. The second area Kangaskhan can be found in is in the grass near the Secret House. There is a 1% chance of Kangaskhan appearing.
great marsh
Get the national pokedex and go to the Great Marsh. trust me i got this info from Bulbapedia.
you find kangaskhan in area 2 of the safari zone in Pokemon leaf Green ... not sure in fire red sorry
once you obtain the national pokedex go to the marsh like safari zone, but it takes a while
You can find it in the rock tunnel, but it is rather rare.
You can find him/her in the safari zone.(If you beat the Elite Four.)
After the game, go to the Great Marsh and search.
you need to find it in the safari zone in area1.
Since it's a Kanto Pokemon, it must be traded from FR/LG.
The baby in a Kangaskhan's pouch is merely a younger Kangaskhan.
There isn't one. Kangaskhan isn't evolved from another Pokemon nor does it evolve.
buy the Pokemon platinum book