1. **Problem Statement:**
Calculate the area of:
i. the circle with radius $r = 3.5$ cm
ii. the square QPQR inscribed in the circle
iii. the shaded region (area of circle minus area of square)
2. **Formulas and Rules:**
- Area of a circle: $$A_{circle} = \pi r^2$$
- Area of a square: $$A_{square} = s^2$$ where $s$ is the side length
- The square QPQR is inscribed in the circle, so its diagonal equals the diameter of the circle.
- Diameter of circle: $$d = 2r$$
- Diagonal of square: $$d = s\sqrt{2}$$
3. **Calculate the area of the circle:**
$$r = 3.5$$
$$\pi = \frac{22}{7}$$
$$A_{circle} = \pi r^2 = \frac{22}{7} \times (3.5)^2 = \frac{22}{7} \times 12.25$$
$$= 22 \times \frac{12.25}{7} = 22 \times 1.75 = 38.5$$
4. **Calculate the side length of the square:**
Diameter of circle:
$$d = 2r = 2 \times 3.5 = 7$$
Diagonal of square equals diameter:
$$d = s\sqrt{2}$$
Solve for $s$:
$$s = \frac{d}{\sqrt{2}} = \frac{7}{\sqrt{2}}$$
Rationalize denominator:
$$s = \frac{7}{\sqrt{2}} \times \frac{\sqrt{2}}{\sqrt{2}} = \frac{7\sqrt{2}}{2}$$
5. **Calculate the area of the square:**
$$A_{square} = s^2 = \left(\frac{7\sqrt{2}}{2}\right)^2 = \frac{49 \times 2}{4} = \frac{98}{4} = 24.5$$
6. **Calculate the shaded region area:**
$$A_{shaded} = A_{circle} - A_{square} = 38.5 - 24.5 = 14$$
**Final answers:**
- Area of the circle = 38.5 cm$^2$
- Area of the square QPQR = 24.5 cm$^2$
- Area of the shaded region = 14 cm$^2$
Circle Square Area 3Bed26
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