Answer:
C
Step-by-step explanation:
The sum of the 3 angles in a triangle = 180°
Subtract the sum of the given angles from 180 to find third angle
third angle = 180° - (80 + 40)° = 180° - 120° = 60°
To find x use the Sine rule, that is
[tex]\frac{x}{sin60}[/tex] = [tex]\frac{5}{sin40}[/tex] ( cross- multiply )
x × sin40° = 5 × sin60° ( divide both sides by sin40° )
x = [tex]\frac{5(sin60)}{sin40}[/tex] ≈ 6.736 → C
