Answer
negative
Work Step by Step
1. With $90^{\circ}\lt \theta\lt 180^{\circ}$, then $-180^{\circ}\lt -\theta \lt -90^{\circ}$
2. This means that $-\theta $ is in QIII, where $x\lt0$ and $y\lt0$
3. Therefore $\\sec( -\theta)\lt 0$
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