Answer:
b ≈ 7.8
Step-by-step explanation:
using the law of sines
∠ A = 180° - 105° - 40° = 180° - 145° = 35° , then
[tex]\frac{b}{sin40}[/tex] = [tex]\frac{7}{sin35}[/tex] ( cross- multiply )
b × sin35° = 7 × sin40° ( divide both sides by sin35° )
b = [tex]\frac{7sin40}{sin35}[/tex] ≈ 7.8 ( to the nearest tenth )
