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: Option B
Explanation
Length of arc = (frac{theta}{360} times 2pi 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)