waecmaths question:
POR is a sector of a circle centre O, radius 4cm, if $\angle PQR={{30}^{{}^\circ }}$. Find, correct to 3 significant figures, the area of sector POR $\pi =\tfrac{22}{7}$
Option A:
19cm2
Option B:
8.38cm2
Option C:
10.5cm2
Option D:
20.9cm2
waecmaths solution:
$\begin{align} & \text{Area of sector}=\frac{\theta }{{{360}^{\circ }}}\times \pi {{r}^{2}}=\frac{{{60}^{\circ }}}{{{360}^{\circ }}}\times \frac{22}{7}\times {{4}^{2}} \\ & =\frac{176}{21}c{{m}^{2}}=8.38c{{m}^{2}} \end{align}$
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