Answer:
9.9 cm
Step-by-step explanation:
Calculate the third angle and then use The Law of Sines.
Sum of angles in triangle is 180°.
angle + 40° + 63° = 180°
angle = 180° - 40° - 63°
angle = 77°
Now we can use the law of sines.
[tex]\frac{x}{\sin 40} = \frac{15}{\sin 77}[/tex]
[tex]x = \frac{15 \cdot \sin 40}{\sin 77}[/tex]
[tex]x \approx 9.895[/tex]
[tex]x \approx 9.9 \text{ cm}[/tex]
