First, multiple-choice questions: CCDBCBDA II. Fill in the blanks: Question 9: 3. Question 10: one fifth. Question 10: 135. Question 1 1: Two points determine a straight line. Question 12: AC AD. Question 13: Square and regular triangle. Question 14: 3/16 π.

Problem 15: 50 problem 16: quadrilateral, pentagonal and hexagonal problem17: 0.3× 60 =18'18× 60 =1080. 2)∠ 1 is getting smaller and smaller. Question 20: 6π. Question 21:30,90. Question 22: (1): n = 8 (2): (n-2) (3): n-1.