Jambmaths question:
An arc of a circle of length 22cm subtends an angle of 3xo at the centre of the circle. Find the value of x if the diameter of the circle is 14cm. [$\pi =\tfrac{22}{7}$]
Option A:
60o
Option B:
120o
Option C:
180o
Option D:
30o
Jamb Maths Solution:
$\begin{align} & \text{Length of an arc}=\frac{\theta }{{{360}^{o}}}\times 2\pi r \\ & 22=\frac{3x}{{{360}^{o}}}\times \frac{2}{1}\times \frac{22}{7}\times {{7}^{2}} \\ & 22=\frac{x}{{{120}^{o}}}\times 44 \\ & x=\frac{22\times {{120}^{o}}}{44}={{60}^{o}} \\\end{align}$
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