The arc of a circle 50 cm long, subtends angle of 75° at the center of the circle. Find correct to 3 significant figures, the radius of the circle. Take \(\pi = \frac{22}{7}\)
A. 8.74cm B. 38.2cm C. 61.2cm D. 76.4cm
Correct Answer: B
Explanation
Length of arc = \(\frac{\theta}{360} \times 2\pi r\) \(50 = \frac{75}{360} \times 2 \times \frac{22}{7} \times r\) \(r = \frac{50 \times 360 \times 7}{75 \times 2 \times 22}\) \(r = \frac{420}{11}\) = 38.18 cm \(\approxeq\) 38.2 cm (3 sig. figs)
