1. **State the problem:** We need to find the ratio of the area of a sector with central angle $\alpha$ radians to the area of the circle inscribed in that sector.
2. **Recall formulas:**
- Area of a sector of a circle with radius $r$ and central angle $\alpha$ (in radians) is given by:
$$\text{Area}_{\text{sector}} = \frac{1}{2} r^2 \alpha$$
- The inscribed circle in the sector is the largest circle tangent to both radii and the arc. Its radius $r_{\text{inscribed}}$ is given by:
$$r_{\text{inscribed}} = r \frac{\sin(\frac{\alpha}{2})}{1 + \sin(\frac{\alpha}{2})}$$
3. **Area of the inscribed circle:**
$$\text{Area}_{\text{inscribed}} = \pi r_{\text{inscribed}}^2 = \pi \left(r \frac{\sin(\frac{\alpha}{2})}{1 + \sin(\frac{\alpha}{2})}\right)^2 = \pi r^2 \left(\frac{\sin(\frac{\alpha}{2})}{1 + \sin(\frac{\alpha}{2})}\right)^2$$
4. **Find the ratio:**
$$\text{Ratio} = \frac{\text{Area}_{\text{sector}}}{\text{Area}_{\text{inscribed}}} = \frac{\frac{1}{2} r^2 \alpha}{\pi r^2 \left(\frac{\sin(\frac{\alpha}{2})}{1 + \sin(\frac{\alpha}{2})}\right)^2}$$
5. **Simplify the ratio:**
$$= \frac{\frac{1}{2} \alpha}{\pi \left(\frac{\sin(\frac{\alpha}{2})}{1 + \sin(\frac{\alpha}{2})}\right)^2} = \frac{\frac{1}{2} \alpha}{\pi \frac{\sin^2(\frac{\alpha}{2})}{(1 + \sin(\frac{\alpha}{2}))^2}} = \frac{\frac{1}{2} \alpha (1 + \sin(\frac{\alpha}{2}))^2}{\pi \sin^2(\frac{\alpha}{2})}$$
6. **Final answer:**
$$\boxed{\text{Ratio} = \frac{\alpha (1 + \sin(\frac{\alpha}{2}))^2}{2 \pi \sin^2(\frac{\alpha}{2})}}$$
This ratio expresses how many times larger the sector's area is compared to the inscribed circle's area, depending only on the central angle $\alpha$.
Sector Inscribed Ratio Dcc957
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