Chapter 7 - Applications of Trigonometric Functions - Section 7.3 The Law of Cosines - 7.3 Assess Your Understanding - Page 559: 23

$c \approx1.69$ $A \approx 65.0^\circ$ $B\approx 65.0^\circ$

1. Use the Law of Cosines, we have $c=\sqrt {(2)^2+(2)^2-2(2)(2)cos50^\circ}\approx1.69$ 2. Use the Law of Sines, $\frac{sinA}{2}=\frac{sin50^\circ}{1.69}$, thus $A=sin^{-1}(\frac{4sin50^\circ}{1.69})\approx 65.0^\circ$ 3. We have $B\approx(180-50-65.0)=65.0^\circ$