A chord of a circle of radius 30 cm makes an angle of 60° at the centre of the circle. Find the areas of the minor major segments.
Let the chord be AB. The ends of the chord are connected to the centre of the circle O to give the triangle OAB.
OAB is an isosceles triangle. The angle at the centre is 60
Area of the triangle $=\frac{1}{2}(30)^{2} \sin 60^{\circ}=450 \times \frac{\sqrt{3}}{2}=389.25 \mathrm{~cm}^{2}$
Area of the sector $O A C B O=\frac{60}{360} \times \pi \times 30 \times 30=150 \pi=471 \mathrm{~cm}^{2}$
Area of the minor segment $=$ Area of the sector $-$ Area of the triangle
$=471-389.25=81.75 \mathrm{~cm}^{2}$
Area of the major segment = Area of the circle - Area of the minor segment
$=(\pi \times 30 \times 30)-81.29$
$=2744.71 \mathrm{~cm}^{2}$