Question 1184699
<pre>
{{{ cos(theta) = 17/35 }}}
{{{ theta = cos^-1(17/35) }}} = 60.94 degrees, or 61 degrees rounded.

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Dear student.  Thanks for the nice comment.  Here are a couple helpful links:

Short and sweet:
https://www.geogebra.org/m/BZ4ERm9h

Longer, with video:
https://www.onlinemathlearning.com/sohcahtoa.html