Question

find the angle in degress that determines the point ( 0.643, -.766)

Answer 1

The angle is determined by the tangent function:

$\begin{gathered} \tan (x)=\frac{-0.766}{0.643} \\ x=\tan ^{-1}(\frac{-0.766}{0.643}) \\ x=-49.98 \end{gathered}$