Answer:
The answer would have to be 16.6666666666667. This can be rounded up or keep the same.
Answer:
The sum of the measures of the interior angles of an octagon =(8−2)180° . The sum of the measures of the interior angles of an octagon is 1080° .
You should be able to multiply 91 by 8 to get the sum of the first 8 tests, then add the score on the 9th test. Then to get the average of the sum of the 9 tests you need to divide it by 9.
((91*8)+78)/9=89.555555555555.... So, 90%