WAEC - Mathematics (2020 - No. 30)
The length of an arc of a circle of radius 3.5 cm is 1\(\frac{19}{36}\) cm. Calculate, correct to the nearest degree , the angle substended by the centre of the circle. [Take \(\pi = \frac{22}{7}\)]
55\(^o\)
36\(^o\)
25\(^o\)
22\(^o\)
Explanation
L = \(\frac{\theta}{360^o}\) = 2\(\pi\)
\(\frac{55}{36} = \frac{\theta}{360^o} \times 2 \times \frac{22}{7} \times 3.5\)
\(\theta = \frac{360 \times 55 \times 44 \times 0.5}{3 \times 44 \times 0.5}\)
= \(\theta = 25^o\)
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