A road curve is to be laid out on a circle. What radius should be used if the track is to change direction by 42^\circ in distance of 44 \text{ m}? (Assume \pi=\frac{22}{7})
- A. 60 m ✓
- B. 66 m
- C. 75 m
- D. 80 m
Correct Answer: A. 60 m
Explanation
Using the arc length formula s = r\theta, where \theta is in radians: 44 = r \times 42 \times \frac{\pi}{180}. Substituting \pi = \frac{22}{7}, we get 44 = r \times 42 \times \frac{22}{7 \times 180} \Rightarrow 44 = r \times \frac{132}{180}. Solving for r: r = \frac{44 \times 180}{132} = \frac{180}{3} = 60 \text{ m}.
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