Chapter 7 - Applications of Trigonometric Functions - Section 7.3 The Law of Cosines - 7.3 Assess Your Understanding - Page 559: 34

$C= 75^\circ$ $a \approx7.14$, $b \approx7.63$

1. Find the third angle $C=(180-50-55)=75^\circ$ 2. Use the Law of Sines, we have $\frac{a}{sin50^\circ}=\frac{b}{sin55^\circ}=\frac{9}{sin75^\circ}$ 3. thus $a=\frac{9sin50^\circ}{sin75^\circ}\approx7.14$, $b=\frac{9sin55^\circ}{sin75^\circ}\approx7.63$