## Trigonometry 7th Edition

$32.6^{\circ}$
First, ensure that your calculator is in radians. On your graphing calculator, press the following sequence of buttons: 1. COS$^{-1}$ 2. ( 3. .8425 4. ) 5. ENTER Therefore, $arccos(.8425)=cos^{-1}(.8425)=.569$ radians. Then, convert this number to degrees by multiplying by $\frac{180}{\pi}$. $.569radians=(.569(\frac{180}{\pi}))^{\circ}\approx32.6^{\circ}$.