Question 70

Find the radius of the circle if the length of its arc is 33 cm whose corresponding central angle is 90° ?

Solution

Central angle = $$\theta = 90$$° and let radius = $$r$$ cm

Length of arc = $$\frac{\theta}{360} \times 2 \pi r = 33$$

=> $$\frac{90}{360} \times 2 \times \frac{22}{7} \times r = 33$$

= $$\frac{1}{4} \times 44 \times r = 33 \times 7$$ cm

=> $$r = \frac{33 \times 7}{11} = 21$$ cm

=> Ans - (A)

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