He finds out about the feast because the servant who was delivering all invitations didn't know how to read, so he went up to Mercutio and asked him if he was one of the invitees on the list, Mercutio wasn't but he took the invite anyway, and that's how Romeo found out.
one question for you, why are you asking? Just read the play if you really want to know, its the easiest way.
Capulet did.
Tybalt recognizes Romeo, a Montague, at his uncle, Lord Capulet's, party, and believes Romeo intends to insult the Capulet family.
Go to the Capulet feast to compare Rosaline to other women.
yes
The Capulet's ball was to take place at night
Juliet recognizes Romeo's voice at the Capulet's feast.
Capulet did.
at capulet's ball/feast.
Tybalt recognizes Romeo, a Montague, at his uncle, Lord Capulet's, party, and believes Romeo intends to insult the Capulet family.
Go to the Capulet feast to compare Rosaline to other women.
yes
Romeo and Juliet first met in a feast at Capulet's house.
Lord Capulet throws a huge feast in "Romeo and Juliet" where Romeo and Juliet first meet each other.
The Capulets throw a big feast in Romeo and Juliet where Romeo and Juliet first meet and fall in love.
He has misgivings about it. He has a feeling that no good will come of it.
Benvolio, Mercutio and some other un named characters.
Tybalt recognizes Romeo's voice at the Capulet's feast and is outraged that he has crashed the party. He informs Lord Capulet about Romeo's presence and insists that he should be removed from the party immediately. Lord Capulet, however, allows Romeo to stay because he does not want to cause a scene at the feast.