We find the reference angle first.

Let sin α = 0.8480, then we have

α = arcsin 0.8480 = 58.0°

Since `sin\ theta` is negative, θ must be in Quadrants III or IV.

So θ = 180° + 58.0° = 238.0° or

θ = 360° − 58.0° = 302.0°

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