1. **Problem statement:** Calculate the perimeter of a compound shape formed by a rectangle and a sector of a circle.
2. **Given:**
- Rectangle length = 37 cm
- Rectangle height = 22 cm
- Sector radius = 37 cm
- Sector angle = 20°
3. **Formula for perimeter:**
The perimeter of the compound shape is the sum of:
- The two vertical sides of the rectangle (each 22 cm)
- The bottom side of the rectangle (37 cm)
- The arc length of the sector
Note: The top side of the rectangle is replaced by the arc of the sector.
4. **Calculate the arc length of the sector:**
The arc length $L$ of a sector with radius $r$ and angle $\theta$ in degrees is given by:
$$L = 2 \pi r \times \frac{\theta}{360}$$
Substitute $r=37$ cm and $\theta=20^\circ$:
$$L = 2 \pi \times 37 \times \frac{20}{360}$$
5. **Simplify the arc length:**
$$L = 2 \pi \times 37 \times \frac{1}{18} = \frac{74 \pi}{18} = \frac{37 \pi}{9}$$
6. **Calculate numerical value:**
$$L \approx \frac{37 \times 3.1416}{9} \approx \frac{116.238}{9} \approx 12.915$$ cm
7. **Calculate the perimeter:**
$$P = 22 + 22 + 37 + 12.915 = 81.915$$ cm
8. **Round to 1 decimal place:**
$$P \approx 81.9$$ cm
**Final answer:** The perimeter of the compound shape is **81.9 cm**.
Compound Shape Perimeter F8A61E
Step-by-step solutions with LaTeX - clean, fast, and student-friendly.