Answer:
34 classes
Step-by-step explanation:
First, subract 180 from 1200. You should get 1020. then do 1020/30. So 34 classes can watch the performance of 180 students.
Answer:
First equation is -425
Second equation is 11.25
Step-by-step explanation:
First equation we can write as

computing
When i=0 -> 
When i=1 -> 
...
When i=7 -> 
then replacing each term we have

For the second equation we'll have 9 terms, solving in a similar fashion
When i=1 -> 
When i=2 ->
When i=3 ->
...
When i=9 ->
So we have 0.25 + 0.50 + 0.75 + 1.00 + 1.25 + 1.50+ 1.75 +2.00 +2.25
Answer: 769.3
Step-by-step explanation:

C=2*3.14*122.5
245/2=122.5
C=769.3
72 times square root of 2