Answer
$\sec 71.8^{\circ}$ = 3.2017
Work Step by Step
Using calculator in degree mode-
$\sec 71.8^{\circ}$ = 3.2016913279
(Finding $\cos$ first and then using reciprocal $\frac{1}{x}$)
Rounding it to four places past the decimal point-
$\sec 71.8^{\circ}$ = 3.2017
