9.c

10. The waist is 5cm and the bottom is 8cm.

1 1.2c

12. Connect DB, and the sum of two sides of the AC triangle is greater than the third side.

1.(2) (3)(4)

2. Germany DC 8

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3.4 4.30 degrees

5.D

6.B

7.D

8.C

9.2 cm