The above literary means 'where place', so where, but present tense 'where' is and can be rendered ca bhfuil - with the fada on ca. Further if you want something like, Where are the girls, Ca bhfuil na cailini? It looks odd to me to write, Ca hait na cailini. Maybe some dialects do, but not come across it...? Requires a subject, ca bhfuil is more where is .... bit picky, really?!
The bhfuil in cá bhfuil na cailíní? is the "are" in "where are the girls?"
The cá in Cá háit? is "what". The cá in cá fhad? is "how".
Interrogatives are slippery customers. In English, can you honestly say that the "how" in "How long is that?" is the same as the "how" in "How did you do that?"?
I do understand, thank you, you could also say that Cen fath, does not literally means what is here translated or Cen ait? which can be used in constructions deemed 'where' cen ait Eireann a bhfuil as? Forgive all errors, tired, but my point was, say to most Gaelic speakers, give me an example of 'where' in Irish and you would not be surprised to find Ca bhfuil offered, alongside others ... as said, bit picky, and you might end up using Ca hait in a situation where it is not the idiom and you want Ca rabh se, Ca bhfuil mo chuid airgead...agus araile....Cut some slack. Ach mar sin fhein, go rabh maith aghad as do fhreaga fhein, a charaid.
If I said Chonaic mé timpiste ar mo shlí abhaile, you would respond Cá háit? (or Cén áit?)
That's "Where?" without any verb to modify it. Unlike English, the interrogative isn't usually used on its own, it needs something to act on (cad é?, cén fáth?, cén chaoi?, cá háit?). And the exercise asked you to translate "Where?" not just the word "where" in isolation.