Chapter 2 - Acute Angles and Right Triangles - Section 2.3 Finding Trigonometric Function Values Using a Calculator - 2.3 Exercises - Page 63: 7

$\sec$ 13$^{\circ}$ 15' = 1.02734878

$\sec$ 13$^{\circ}$ 15' First, convert to a fraction $\sec$ 13$^{\circ}$ $\frac{15}{60}$ Convert the fraction to a decimal $\frac{15}{60}$ = 0.25 Therefore: $\sec$ 13$^{\circ}$ 15' = $\sec$ 13.25$^{\circ}$ $\sec$ 13.25$^{\circ}$ = $\frac{1}{\cos13.25}$ $\frac{1}{\cos13.25}$ = 1.02734878 $\sec$ 13$^{\circ}$ 15' = 1.02734878