Chapter 7 - Section 7.3 - The Ambiguous Case - 7.3 Problem Set - Page 389: 10

$B = 27.131^\circ$ $B' = 152.869^\circ$

$\sin{B} = \dfrac{b \sin{A}}{a} = \dfrac{40 \times \sin{20^\circ}}{30} $ $\sin{B} = 0.456$ $B = 27.131^\circ$ $B' = 180-B = 152.869^\circ$ $A+B' =20+152.869 = 172.869^\circ <180$