Chapter 2 - Acute Angles and Right Triangles - Section 2.3 Finding Trigonometric Function Values Using a Calculator - 2.3 Exercises - Page 63: 29

$\theta$ $\approx$ 68.67432914$^{\circ}$

$\sec$ $\theta$ = 2.7496222 Therefore: $\cos$ $\theta$ = $\frac{1}{\sec\theta}$ $\cos$ $\theta$ = $\frac{1}{2.7496222}$ $\cos$ $\theta$ = 0.36366863 $\theta$ = $\cos$$^{-1}$ 0.36366863 Utilizing the calculator: $\theta$ $\approx$ 68.67432914$^{\circ}$