JAMB - Mathematics (2002 - No. 24)
A chord of a circle subtends an angle of 120° degrees at the centre of a circle of diameter 4√3 cm. Calculate the area of the major sector.
4π cm2
32 π cm2
16 π cm2
8 π cm2
설명
Diameter = 4\(\sqrt{3}\) cm
radius = 2\(\sqrt{3}\) cm
Area of major sector = \(\frac{\theta}{360} \times \pi r^{2}\)
\(\theta = 360 - 120 = 240°\)
= \(\frac{240}{360} \times \pi \times 12\)
= \(8\pi cm^{2}\)