waecmaths question:
An arc subtends an angle of 72o at the centre of a circle. Find the length of the arc if the radius of the circle is 3.5cm [Take $\pi=\frac{22}{7}$
Option A:
6.6cm
Option B:
8.8cm
Option C:
4.4cm
Option D:
2.2cm
waecmaths solution:
$\begin{align} & \theta =72{}^\circ \\ & r=3.5cm \\ & l=\frac{\theta }{360{}^\circ }\times 2\pi r \\ & l=\frac{72{}^\circ }{360{}^\circ }\times 2\times \frac{22}{7}\times 3.5cm \\ & l=\frac{1}{5}\times 2\times \frac{22}{7}\times \frac{7}{2}cm=4.4cm \\\end{align}$
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