To find the suum the formula is (n - 2) x 180 degrees
Answer:

Step-by-step explanation:
Multiply by 2:
2n = Z(A - m)
Divide by Z:
Subtract A:

Multiply by -1:

Answer:
1.2 degrees
Step-by-step explanation:
Answer: 22% of the pages are filled up
Step-by-step explanation: 900/9= 100 78% of 100 is 78
22+78=100 therefore reaching 100 percent. since 78% is empty that means 22% is being used.