Learn Italian: Siamo tranquilli visto che la protesta è pacifica. - We are calm seeing that the protest is peaceful.

While both introduce a reason, visto che (literally "seen that") translates closer to "seeing that", "since", or "given that". It is generally used to state a reason that is based on a clear, observable fact or an already known situation, rather than simply answering a "why" question.

Could I change the order of the sentence and put visto che at the beginning?

Yes! This is a major advantage of visto che. While starting a sentence with perché (meaning "because") can sometimes feel clumsy or informal in Italian, starting with visto che sounds perfectly natural. You could comfortably say: Visto che la protesta è pacifica, siamo tranquilli.

Could I use dato che instead of visto che in this sentence?

Absolutely. Dato che ("given that") and visto che are practically interchangeable in everyday Italian. They both function exactly the same way to introduce a known cause or fact, so dato che la protesta è pacifica works perfectly here.

Why do the adjectives tranquilli and pacifica have different endings in this sentence?