WAEC - Mathematics (2019 - No. 28)

Find the angle at which an arc of length 22 cm subtends at the centre of a circle of radius 15cm.  [Take \(\pi = \frac{22}{7}\)]
70\(^o\)
84\(^o\)
96\(^o\)
156\(^o\)

Explanation

L = \(\frac{\theta}{360} \times 2 \pi r\)

22 = \(\frac{\theta}{360} \times 2 \times \frac{22}{7} \times 15\)

\(\theta = \frac{22 \times 360 \times 7}{2 \times 22 \times 15}\)

\(\theta\) = 84\(^o\) 

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