How do you use a calculator to evaluate $cos78^circ11' 58''$ ?

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Answer 1 · 2017-02-28T14:13:25

0.2046

First, convert 11 minutes an 58 seconds to centum system:

$11' --> (1h(11))/(60) = 18%$ --> or 0.18 of an hour.
$58'' --> (1'(58))/(60) = 97%$ --> or 0.0097 of an hour

$cos 78^@ 11' 58"" --> cos 78^@1897$

Calculator gives --> $cos 78^@1897 = 0.2046$

How do you use a calculator to evaluate cos78^circ11' 58''cos78^circ11' 58''?