Answer
$1.36076507875$
Work Step by Step
Make sure that the setting for angles is "radians".
$\sec^{-1}x$ is evaluated as $\displaystyle \cos^{-1}(\frac{1}{x}).$
Keys:
"shift" or "2nd function"
"cos"
numerical keypad: (4.7963825)
"="
yields
$1.36076507875$
