c？

C

A

C

C

A

A

right angle

1 1 or 13

70 degrees

70 degrees

seven

12cm

I draw this by myself, and I can't type.

Solve the problem yourself.

63

1.C

2.C

3. Selective SelectiveServiceSystem

5.B

6. The triangle is very stable

7.DC=AB

8.sss

9ss

10.sss