## Thinking Mathematically (6th Edition)

$a \approx 182$ in.
RECALL: In a right triangle, $\sin{A} = \dfrac{\text{length of opposite side}}{\text{length of hypotenuse}} \\\cos{A} = \dfrac{\text{length of adjacent side}}{\text{length of hypotenuse}} \\\tan{A} = \dfrac{\text{length of opposite side}}{\text{length of adjacent side}}$ Use the cosine formula to obtain: $\cos{A} = \dfrac{\text{length of adjacent side}}{\text{length of hypotenuse}} \\\cos{34^o}=\dfrac{b}{220}$ Multiply 220 to both sides of the equation to obtain: $\cos{34^o} \cdot 220 = b \\182.388266 = b \\182 \approx a$ Thus, $a \approx 182$ in.