Triangle ABC Angle A = 74° a = 126 b = 84 Use the sine rule [tex] \frac{a}{sin A} = \frac{b}{sin B} [/tex] Plug in the given [tex] \frac{126}{sin(74)} = \frac{84}{sin(B)} [/tex] Cross multiply 126 × sin(B) = 84 × sin(74) Divide by 126 [tex] \frac{126sin(B)}{126} = \frac{84sin(74)}{126}
[/tex] 126 and 126 cancels out sin(B) = [tex] \frac{84sin(74)}{126} [/tex] take sin inverse ([tex]sin^{-1} [/tex]) B = [tex] sin^{-1} [/tex] ([tex] \frac{84sin(74)}{126} [/tex]) B = 39.85° = 39.9°
