Question

Find the value of b. Round to the

nearest tenth.
A
19°
B
142°
b
b = [?]
42
C

Answer 1

79.4

Explanation:

42/sin19 = b/sin142

b(sin19) = 42(sin142)

b = 42(sin142) / sin19 = 79.4

Answer 2

78.9

Explanation:

Law of sines:

`(a)/(Sin \ A)=(b)/(Sin \ B) =(c)/(Sin \ C)`

To find the value of b, we consider,

`(b)/(Sin \ B)=(a)/(Sin \ A)`

Substitute the value a, A and B,

`(b)/(Sin \ 142^\circ)=(42)/(Sin \ 19)\\\\\\(b)/(0.62)=(42)/(0.33)\\\\`

`b =(42)/(0.33)*0.62\\\\\\b= 78.9`