1. **State the problem:** Find the area of the shaded region, which is the area of the sector of a circle with radius $32$ and central angle $45^\circ$ minus the area of the triangle formed by the two radii and the chord.
2. **Formula for sector area:** The area of a sector with radius $r$ and central angle $\theta$ (in degrees) is given by
$$\text{Area}_{\text{sector}} = \frac{\theta}{360} \pi r^2$$
3. **Calculate the sector area:**
$$\text{Area}_{\text{sector}} = \frac{45}{360} \pi (32)^2 = \frac{1}{8} \pi \times 1024 = 128\pi$$
4. **Find the area of the triangle:** The triangle is isosceles with two sides equal to the radius $32$ and an included angle of $45^\circ$.
The area of a triangle with two sides $a$, $b$ and included angle $\theta$ is
$$\text{Area}_{\triangle} = \frac{1}{2}ab \sin(\theta)$$
Here, $a = b = 32$, $\theta = 45^\circ$.
5. **Calculate the triangle area:**
$$\text{Area}_{\triangle} = \frac{1}{2} \times 32 \times 32 \times \sin(45^\circ) = 512 \times \frac{\sqrt{2}}{2} = 256\sqrt{2}$$
6. **Approximate the triangle area:**
$$256\sqrt{2} \approx 256 \times 1.4142 = 362.0$$
7. **Find the shaded area:**
$$\text{Shaded area} = \text{Area}_{\text{sector}} - \text{Area}_{\triangle} = 128\pi - 256\sqrt{2}$$
8. **Approximate the shaded area:**
$$128\pi \approx 128 \times 3.1416 = 402.1$$
$$\text{Shaded area} \approx 402.1 - 362.0 = 40.1$$
9. **Final answer:**
The shaded area is
$$128\pi - 256\sqrt{2} \approx 40.1$$
This matches none of the options exactly, but the problem's options combine $\pi$ terms and decimals. The closest matching form is $128\pi + 45.2$ if the decimal is the difference, but the correct exact form is $128\pi - 256\sqrt{2}$.
Since the problem asks to leave the answer in terms of $\pi$ and round decimals, the shaded area is:
$$128\pi - 362.0$$
or approximately $40.1$.
---
"slug": "sector shaded",
"subject": "geometry",
"desmos": {"latex": "y=0", "features": {"intercepts": true, "extrema": true}},
"q_count": 1
Sector Shaded A4990B
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