1: Since bisects means cuts in half, it would be 7 centimeters.
2: Again, since bisects means cuts in half, then you would multiply 6 3/4 by two (because it's one of the halves this time) and you would get 13 1/2.
3: Do the same thing as before. It's the same thing as before. It's 9.
4: This one's the same concept as 1. Split it in half. 7.4.