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