2.Sina = root number 3 ∠ A = 60.
3.5/ 12
4.BC/AC= radical number 3 to 3 BC/AB= 1/2.
5. 1: root number 3:2
6.4/5
7.24
8. 1
9.60
10.A
1 1.A
12.C
13.A
14.A
15.A
16.C
17.A
18.D
I made the above answer myself, not a guess, and I guarantee it with my reputation. (I am a schoolmaster)