Nomer 2-4 gimana yah?

2). Dik:
LM (k) = 10 cm
KM (l) = 4√3 cm
∠K (K)= 60°

Dit:
Cos L = ............. ?

Jwb:
k/sin K = l/sin L
10/sin 60° = 4√3/sin L
10/(1/2√3) = 4√3/sin L
sin L = (4√3 x 1/2√3)/10
sin L = (2 x 3)/10
sin L = 6/10
sin L = 3/5

Kemudian cari cos L,,
sin = depan (d)/miring (m)
cos = samping (s)/miring (m)

Karena "d" dan "m" sudah diketahui, maka cari "s" nya
s = √(m² - d²)
s = √(5² - 3²)
s = √(25 - 9)
s = √16
s = 4

Jadi, cos L adalah:
cos L = samping/miring = 4/5

3).
a) Dik:
sin A = 53°
a = 14 cm
b = 10 cm

Dit:
sin B = ....... ?

Jwb:
a/sin A = b/sin B
14/sin 53° = 10/sin B
14/0,798 = 10/sin B
sin B = (0,798 x 10)/14
sin B = 7,98/14
sin B = 0,57

b). Dik:
b = 4 cm
c = 6 cm
sin B = 25°

Dit:
sin C = .......... ?

Jwb:
b/sin B = c/ sin C
4/sin 25° = 6/sin C
4/0,422 = 6/sin C
sin C = (0,422 x 6)/4
sin C = 2,532/4
sin C = 0,633

4). Dik:
b = 2,8 cm
∠A = 53°
∠B = 61°

Dit:
a = ....... ?

Jwb:
a/sin A = b/sin B
a/sin 53° = 2,8/sin 61°
a/0,798 = 2,8/0,874
a = (0,798 x 2,8)/0,874
a = 2,2344/0,874
a = 2,556