Questions & Answers about Это салон, в котором мне быстро высушили чёлку феном.
Both can mean where in English, but they work a little differently in Russian.
- где = where
- в котором = literally in which
So:
- Это салон, где... = This is the salon where...
- Это салон, в котором... = This is the salon in which...
In this sentence, в котором sounds a bit more explicit and slightly more formal/bookish than где. In everyday speech, many people would also say:
- Это салон, где мне быстро высушили чёлку феном.
Both are natural.
Because the pronoun который has to match both:
- the noun it refers to, and
- the case required by the preposition.
It refers back to салон, which is:
- masculine
- singular
And because the phrase is в ... meaning in ..., Russian uses the prepositional case here.
So:
- base form: который
- masculine singular prepositional: котором
That gives:
- в котором = in which