WAEC 2023 · Paper 1 · Q33

Plane mensuration

The angle of a sector of a circle of radius $3.4\text{ cm}$ is $115^\circ$ . Find the area of the sector. $\left[\text{Take }\pi = \frac{22}{7}\right]$

Worked solution (try it first)

Area of a sector $= \frac{\theta}{360} \times \pi r^2$ , with $r^2 = 3.4^2 = 11.56$ .
$\frac{22}{7} \times 11.56 \approx 36.33$ , so the area is $\frac{115}{360} \times 36.33 \approx 11.6\text{ cm}^2$ , option B.

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