Answer
$\theta\approx 2.3 $ rad$ \quad$ and$ \quad \theta\approx$ 4 rad
Work Step by Step
For any real number $s$ represented by a directed arc on the unit circle,
$\sin s=y\quad \cos s=x \quad \displaystyle \tan s=\frac{y}{x} (x\neq 0)$
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On the unit circle, 2 points have x-coordinates equal to $-0.65$.
These are encircled on the image below.
These points represent directed arcs for angles
$\theta\approx 2.3 $rad$ \quad$ and$ \quad \theta\approx$ 4 rad