Where was ballroom dancing performed?
Most American Standard ballroom judging criteria involve :
How many areas of contact are there in ballroom dancing?
This actually depend on the style of Ballroom you are dancing. In Latin or Rhythm, you will only have two points of contact, which would be both your arms. If you are dancing Smooth or standard style dances, you will have three points of contact; both of your arms, and your hips.
Is ballroom dancing a competitive sport?
Yes there are alot of ballroom competitions. Whether or not you would consider it a sport is up to you though.