Question

Somebody help me with this please .

Answer 1

Step-by-step explanation:

12. Cos 60° = 8/c

0,5 = 8/c

0,5 c = 8

c = 16

D² = V16²-8²

= V256-64

=V192 = V16×12 = 4V12

= 4V4×3 = 8V3

13. Cos 30° = 6/b

V3/2 = 6/b

V3 b = 12

b = 12/V3

b/Sin B = a /sin A

b/Sin90° = 6/ sin 60°

b = 6

1 V3/2

b× V3 = 6

2

b = 6× 2/V3

= 12/V3