0∘≤θ<90∘0^{\circ} \leq \theta<90^{\circ}0∘≤θ<90∘
90∘<θ≤180∘90^{\circ}<\theta \leq 180^{\circ}90∘<θ≤180∘
0∘<θ≤90∘0^{\circ}<\theta \leq 90^{\circ}0∘<θ≤90∘
90∘≤θ<180∘90^{\circ} \leq \theta<180^{\circ}90∘≤θ<180∘
